No you don't, you just need to ensure you're riding a straight course and not leaning the bike over. Hitting rails while cornering is what will catch you out. For those in Melbourne, and to a lesser extent Adelaide where tramlines can be encountered, learn how to bunny-hop sideways, or at least pop a wheelie to lift the front over when dealing with tracks along the road. With the front wheel across the rear will follow with enough of an angle to the rail to not get caught.ColinOldnCranky wrote:Train tracks are ALWAYS chancy. As suggested already, you must go at right angles.
Do you pump your tyre to the max psi? and my bad experience today
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Re: Do you pump your tyre to the max psi? and my bad experience today
Postby Duck! » Sun Jan 21, 2018 10:06 pm
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Re: Do you pump your tyre to the max psi? and my bad experience today
Postby Duck! » Sun Jan 21, 2018 10:23 pm
Only true to a point. Tyres are faster at a pressure slightly below the rated maximum, and that exact pressure is mostly related to rider weight, and slightly affected by the construction of the particular tyre. The sweet spot, as alluded to previously, is the pressure that allows the tyre to "sag" by 15% of its profile height when weighted. Excessively soft pressure increases the friction within the tyre itself, and between the tyre and tube as it deforms more, and is therefore slower. Excessively high pressure is also slower, as the tyre will tend to bounce rather than conform to surface irregularities in the road, and as a result of the bounce the rotation speed gets out of phase with the ground speed, which also increases friction and slows you down.sammutd88 wrote: Less pressure is not slower....
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Re: Do you pump your tyre to the max psi? and my bad experience today
Postby NASHIE » Mon Jan 22, 2018 12:25 am
I think Colin is right in regards to inexperienced riders i.e. the OP. Not many rail crossings in Perth and most are at right angles, but a set in Bassendean (Railway Parade) are at 45 degrees to a straight section of road and often take riders down. Not disagreeing, but sideways bunny-hops are probably skipping a few chapters in the 'How to safely ride a bike' handbookDuck! wrote:No you don't, you just need to ensure you're riding a straight course and not leaning the bike over. Hitting rails while cornering is what will catch you out. For those in Melbourne, and to a lesser extent Adelaide where tramlines can be encountered, learn how to bunny-hop sideways, or at least pop a wheelie to lift the front over when dealing with tracks along the road. With the front wheel across the rear will follow with enough of an angle to the rail to not get caught.ColinOldnCranky wrote:Train tracks are ALWAYS chancy. As suggested already, you must go at right angles.
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Re: Do you pump your tyre to the max psi? and my bad experience today
Postby human909 » Mon Jan 22, 2018 2:58 am
Girls on bikes with streamers on the handlebars seem to cope just fine with the tram tracks the are everywhere around me. Likewise the dutch cope just fine with their trams.
Except in many areas in Melbourne requiring cyclist to cross at right angles difficult. Plenty of roads and bike lanes go ACROSS tram tracks and angles not at all at right angles.NASHIE wrote:I think Colin is right in regards to inexperienced riders i.e. the OP.
That sort of advice is similar advice to "don't drive in the rain as your car will have less grip".
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Re: Do you pump your tyre to the max psi? and my bad experience today
Postby Alex Simmons/RST » Mon Jan 22, 2018 7:39 am
Don't assume the gauge markings accurately reflect the actual tyre pressure either. Most pump gauges are wrong, some are worse than others.Philistine wrote:This thread prompted me to take a magnifying glass and check the dial gauge on my foot pump. The gauge has gradually become unreadable to the naked eye (my naked eye anyway), but I have always run with the idea (don't ask me where I got it from) that the 12 o'clock position, which I could see easily enough, corresponded to 7 bar (101.5 psi) and so that was my target when inflating my tyres. To my horror, I found that 12 o'clock position was only 5 bar (72.5 psi), which could explain why I get so many pinch flats.
Floor pumps do however tend to be reasonably repeatable in their wrongness, so if you can check your pump's gauge calibration by comparing with a known accurate gauge then you can mark on the gauge what's actually correct for your needs.
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Re: Do you pump your tyre to the max psi? and my bad experience today
Postby g-boaf » Mon Jan 22, 2018 9:21 am
I coped alright with the tram tracks in Innsbruck in very wet conditions. I remembered all of the people on here talking about bad experiences with tram tracks in Melbourne over the years and just made sure to cross the tracks at a bit of an angle. And I hardly ever encounter tram tracks up here in Sydney.human909 wrote:A good degree of caution is often warranted. But definitive statements about tram/train tracks needing to be crossed at right angles or are extremely treacherous is really overstating things.
Girls on bikes with streamers on the handlebars seem to cope just fine with the tram tracks the are everywhere around me. Likewise the dutch cope just fine with their trams.
Except in many areas in Melbourne requiring cyclist to cross at right angles difficult. Plenty of roads and bike lanes go ACROSS tram tracks and angles not at all at right angles.NASHIE wrote:I think Colin is right in regards to inexperienced riders i.e. the OP.
That sort of advice is similar advice to "don't drive in the rain as your car will have less grip".
Well, the inaccurate gauge marking is still no problem, as you still inflate the tyre to the same amount each time or near enough to it.Alex Simmons/RST wrote:Don't assume the gauge markings accurately reflect the actual tyre pressure either. Most pump gauges are wrong, some are worse than others.
Given most of us are not doing 40km/h average speeds on our rides (the standard on this forum by which one is now marked as a fit rider), the difference of 5psi is probably meaningless.
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Re: Do you pump your tyre to the max psi? and my bad experience today
Postby BJL » Mon Jan 22, 2018 9:24 am
Now who's overstating things?human909 wrote:A good degree of caution is often warranted. But definitive statements about tram/train tracks needing to be crossed at right angles or are extremely treacherous is really overstating things.
Girls on bikes with streamers on the handlebars seem to cope just fine with the tram tracks the are everywhere around me. Likewise the dutch cope just fine with their trams.
Except in many areas in Melbourne requiring cyclist to cross at right angles difficult. Plenty of roads and bike lanes go ACROSS tram tracks and angles not at all at right angles.NASHIE wrote:I think Colin is right in regards to inexperienced riders i.e. the OP.
That sort of advice is similar advice to "don't drive in the rain as your car will have less grip".
But really,
https://www.youtube.com/watch?v=YfeQvbIFBks
So whatever you say about some of us being over cautious, you can't deny the fact that crossing tracks at right angles is the safest way where possible.
So if you can easily cross the tracks at right angles and you don't because that's for morons who can't ride bicycles, kudos to you. Just don't complain if you fall. And don't criticize others for taking precautions either. I'll take whatever precautions I think are necessary to enjoy my rides and get home safely.
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Re: Do you pump your tyre to the max psi? and my bad experience today
Postby fat and old » Mon Jan 22, 2018 11:06 am
No offence to the OP intended here, but this section seems to have been overlooked.fauziozi wrote:Hi guys,
newbie here, just started cycling in Melbourne -- commuting from Kew to Dockland.
today was somewhat a dangerous ride for me, and I think it was caused by the tyre being over-inflated. Though, I might be wrong.
...................................................................................................................
Worst one was when I was turning right on a traffic light, and there was a tram line. The tyre immediately slide into the rail-crack and I almost fell over right in the middle of the intersection.
Fauzioni is a self confessed newbie, asking for advice. A couple of weeks in and he's encountered the downside of tramtracks. He's not human909 or G-boaf with their multi-hemisphere, ride anywhere experience or confidence. Sure, tracks are simple enough after a bit of experience (both dry and wet!) but until then shooting the messenger based on your own uber-confidence is a bit harsh.
Those girls with streamers regularly pass me on St Georges Rd...they're fast! And experienced. And we all know that the Dutch are the inspiration for the current crop of DC comics superheroes shows on Netflix.Girls on bikes with streamers on the handlebars seem to cope just fine with the tram tracks the are everywhere around me. Likewise the dutch cope just fine with their trams.
So you were forewarned? Like others are trying to do for the OP?I coped alright with the tram tracks in Innsbruck in very wet conditions. I remembered all of the people on here talking about bad experiences with tram tracks in Melbourne over the years and just made sure to cross the tracks at a bit of an angle
Come on blokes, not everyone is experienced as you all. Let the forum work for a fella.
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Re: Do you pump your tyre to the max psi? and my bad experience today
Postby fat and old » Mon Jan 22, 2018 11:08 am
Aye? When did that happen? I must be clinically deadg-boaf wrote:
Given most of us are not doing 40km/h average speeds on our rides (the standard on this forum by which one is now marked as a fit rider)
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Re: Do you pump your tyre to the max psi? and my bad experience today
Postby g-boaf » Mon Jan 22, 2018 12:07 pm
Oh, I read it in a reply recently. Suffice to say it'd be almost suicide to attempt it on my regular ride and it's just not going to happen anyway.fat and old wrote:Aye? When did that happen? I must be clinically deadg-boaf wrote:
Given most of us are not doing 40km/h average speeds on our rides (the standard on this forum by which one is now marked as a fit rider)
Well, apologies then for having read by chance some things about that... They aren't common to me as we don't have a tram network in Sydney so it's hardly like I have to ride over them all the time. Just remembered to be careful and not go blasting across them, that's just me being cautious. And I'm hardly criticising the OP for asking.fat and old wrote:So you were forewarned? Like others are trying to do for the OP?I coped alright with the tram tracks in Innsbruck in very wet conditions. I remembered all of the people on here talking about bad experiences with tram tracks in Melbourne over the years and just made sure to cross the tracks at a bit of an angle
Come on blokes, not everyone is experienced as you all. Let the forum work for a fella.
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Re: Do you pump your tyre to the max psi? and my bad experience today
Postby fat and old » Mon Jan 22, 2018 1:05 pm
Yeah, true. Apologies for seeming harsh, to you and human.g-boaf wrote:And I'm hardly criticising the OP for asking.
OP should still be wary of the rotten things tho.
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Re: Do you pump your tyre to the max psi? and my bad experience today
Postby Alex Simmons/RST » Mon Jan 22, 2018 1:23 pm
Not sure what 40km/h speeds have to do with it.g-boaf wrote:Well, the inaccurate gauge marking is still no problem, as you still inflate the tyre to the same amount each time or near enough to it.Alex Simmons/RST wrote:Don't assume the gauge markings accurately reflect the actual tyre pressure either. Most pump gauges are wrong, some are worse than others.
Given most of us are not doing 40km/h average speeds on our rides (the standard on this forum by which one is now marked as a fit rider), the difference of 5psi is probably meaningless.
As to pumps, many are much worse than being 5psi wrong. I've seen inaccuracies of up to 20psi. It makes a difference to comfort levels, ability to avoid pinch flats, bike handling and wet weather riding safety as well.
Not everyone can use the same pump every time so knowing what your pump gauge actually reads compared with a standard is helpful.
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Re: Do you pump your tyre to the max psi? and my bad experience today
Postby ColinOldnCranky » Mon Jan 22, 2018 4:19 pm
http://www.bicycles.net.au/forums/index ... f1f1531a69#NASHIE wrote:I think Colin is right in regards to inexperienced riders i.e. the OP. Not many rail crossings in Perth and most are at right angles, but a set in Bassendean (Railway Parade) are at 45 degrees to a straight section of road and often take riders down. Not disagreeing, but sideways bunny-hops are probably skipping a few chapters in the 'How to safely ride a bike' handbookDuck! wrote:No you don't, you just need to ensure you're riding a straight course and not leaning the bike over. Hitting rails while cornering is what will catch you out. For those in Melbourne, and to a lesser extent Adelaide where tramlines can be encountered, learn how to bunny-hop sideways, or at least pop a wheelie to lift the front over when dealing with tracks along the road. With the front wheel across the rear will follow with enough of an angle to the rail to not get caught.ColinOldnCranky wrote:Train tracks are ALWAYS chancy. As suggested already, you must go at right angles.
Even experienced riders would be well advised to take it slow and blunt the angle if running on thin tyres. Those that think they are better than that live in a fools paradise. The laws of physics and the properties of materials apply to everyone. And the space between the road and the rail is the same space whether you are Cadell Evans or just some clunker except the clunker is more likely to have a tyre fatter than that space than those who like to think they are an elite rider.
In the case of Railway Parade that you allude to we have had riders on this forum sometimes finding their wheels sliding to the right directly onto the traffic line. Various parties such as Railways, the council and others have ducked and weaved and diverted responsibility away from themselves. (Maybe someone has something to report if that is still the case of Railway Parade track crossing.)
(For the record the angle is even sharper than you report, about 30 degrees. Erk! Watch out for the rain.)
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Re: Do you pump your tyre to the max psi? and my bad experience today
Postby RobertL » Mon Jan 22, 2018 4:23 pm
Those train tracks don't look like they're the best. They seen to catch out some riders who look to me to be approaching at a safe angle.But really,
https://www.youtube.com/watch?v=YfeQvbIFBks
But there are a large number of people who crash on that video after safely negotiating the first rail and then turning to take the second rail at a shallower angle. It's like they think that they've made it to safety, but they've only done half the job.
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Re: Do you pump your tyre to the max psi? and my bad experience today
Postby ColinOldnCranky » Mon Jan 22, 2018 10:55 pm
I like the pair of Mormons(?) at 0:52. Those guys have some unresolved issues.RobertL wrote:Those train tracks don't look like they're the best. They seen to catch out some riders who look to me to be approaching at a safe angle.But really,
https://www.youtube.com/watch?v=YfeQvbIFBks
But there are a large number of people who crash on that video after safely negotiating the first rail and then turning to take the second rail at a shallower angle. It's like they think that they've made it to safety, but they've only done half the job.
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Re: Do you pump your tyre to the max psi? and my bad experience today
Postby AUbicycles » Tue Jan 23, 2018 7:28 am
For tyre pressure, don't underestimate the thumb test. It won't compete against a pressure gauge for accuracy but I am guessing that members here test their tyres more regularly with the thumb test than with a floor pump.
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Re: Do you pump your tyre to the max psi? and my bad experience today
Postby sammutd88 » Tue Jan 23, 2018 8:29 pm
Yikes....all correct but I dunno about measuring a 15% sag. Good luck with that one. The difference in rolling resistance between what’s comfortable and what’s fastest is so negligible to a recreational rider that comfort and handling should take priority.Duck! wrote:Only true to a point. Tyres are faster at a pressure slightly below the rated maximum, and that exact pressure is mostly related to rider weight, and slightly affected by the construction of the particular tyre. The sweet spot, as alluded to previously, is the pressure that allows the tyre to "sag" by 15% of its profile height when weighted. Excessively soft pressure increases the friction within the tyre itself, and between the tyre and tube as it deforms more, and is therefore slower. Excessively high pressure is also slower, as the tyre will tend to bounce rather than conform to surface irregularities in the road, and as a result of the bounce the rotation speed gets out of phase with the ground speed, which also increases friction and slows you down.sammutd88 wrote: Less pressure is not slower....
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Re: Do you pump your tyre to the max psi? and my bad experience today
Postby BJL » Wed Jan 24, 2018 1:14 pm
It wouldn't be that hard. Sit the bike on a smooth surface unloaded and measure the distance between the surface and the outside edge of the rim directly under the axle. Then sit on the bike and get someone to repeat measurement. Work out if the difference is 15% of the unload measurement or not.sammutd88 wrote:
Yikes....all correct but I dunno about measuring a 15% sag. Good luck with that one. The difference in rolling resistance between what’s comfortable and what’s fastest is so negligible to a recreational rider that comfort and handling should take priority.
Someone out there has probably made a tool to do it for you. If not, invent one and use some imaginative marketing to convince everyone that it's an essential tool for cycling and the missing key to being faster than your mates out on the road.
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Re: Do you pump your tyre to the max psi? and my bad experience today
Postby Philistine » Thu Jan 25, 2018 9:40 am
I forgot to mention in my earlier post that I can inflate a 23mm tyre from flat to the 12 o'clock position on the gauge (72.5 psi) in about 25 strokes but it requires an enormous effort to go even a little bit higher. I wondered if my gauge was reading low and so I sprung for a new floor pump ($19.95 from Letour, arrived in 2 days, kudos to them). The rear tyre of my roadie was already at about 5.5 bar (on the old pump gauge), and it took only half a dozen strokes to move it up to 7 bar (on the new gauge). I realize this is a bit light on scientific objectivity (2 different pumps, two different gauges neither of which is necessarily accurate), but the tyre feels harder than it has felt since the last time the bike came back from a tune-up.Alex Simmons/RST wrote: Don't assume the gauge markings accurately reflect the actual tyre pressure either. Most pump gauges are wrong, some are worse than others.
Floor pumps do however tend to be reasonably repeatable in their wrongness, so if you can check your pump's gauge calibration by comparing with a known accurate gauge then you can mark on the gauge what's actually correct for your needs.
It is reasonably clear to me that my old pump is badly worn (or perhaps was not very good to begin with), and I have been consistently underinflating my tyres as a result.
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Re: Do you pump your tyre to the max psi? and my bad experience today
Postby seadan44 » Sat Jan 27, 2018 3:42 pm
I am new to the forum and reasonably green with cycling so would like to ask for you expertise.
Sorry to hijack the thread a bit but this is the exact predicament that I find myself with.
Firstly I have a 2013 Giant Defy 2 running on 2015 Ksyrium Elite SL's shod with Schwalbe Durano Plus 700 x 25's.
I am now down to 86kg from 97kg which I have lost over the last 6 months (thanks to the bike) so will be continuing.
The problem I have is that I moved from the standard Giant SR2 wheels and tyres mentioned above, to the Ksyriums and have unfortunately had 5 punctures in the last week and a half.
The punctures are all over the place and I have checked the wheels and tyres for sharps. I have as before been running them at max 115psi but prior to this wheelset had no issues with punctures.
So for the more knowledgeable than me, is the fact the rims are stiffer and I believe wider than standard causing issues or is the pressure too much with these rims?
Thanks for your advice and sorry for the novel .
Sean
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Re: Do you pump your tyre to the max psi? and my bad experience today
Postby foo on patrol » Sat Jan 27, 2018 6:04 pm
Simple answer, no!seadan44 wrote:Hi everyone,
I am new to the forum and reasonably green with cycling so would like to ask for you expertise.
Sorry to hijack the thread a bit but this is the exact predicament that I find myself with.
Firstly I have a 2013 Giant Defy 2 running on 2015 Ksyrium Elite SL's shod with Schwalbe Durano Plus 700 x 25's.
I am now down to 86kg from 97kg which I have lost over the last 6 months (thanks to the bike) so will be continuing.
The problem I have is that I moved from the standard Giant SR2 wheels and tyres mentioned above, to the Ksyriums and have unfortunately had 5 punctures in the last week and a half.
The punctures are all over the place and I have checked the wheels and tyres for sharps. I have as before been running them at max 115psi but prior to this wheelset had no issues with punctures.
So for the more knowledgeable than me, is the fact the rims are stiffer and I believe wider than standard causing issues or is the pressure too much with these rims?
Thanks for your advice and sorry for the novel .
Sean
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Re: Do you pump your tyre to the max psi? and my bad experience today
Postby seadan44 » Sat Jan 27, 2018 7:02 pm
'No' the pressures ok.... or,
'No' the rim width is not creating a wider contact patch thereby exposing more 'unprotected' rubber..... or,
'No' you are not normally attracted to other men, but find yourself strangely curious on just this 'one' occassion
Just joking, but would like a little clarification as I am getting tired of having to change tubes on the side of the bike path at 5 in the morning.
Thanks
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Re: Do you pump your tyre to the max psi? and my bad experience today
Postby fat and old » Sat Jan 27, 2018 7:29 pm
Oh, and Foo means no to the last two questions
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Re: Do you pump your tyre to the max psi? and my bad experience today
Postby seadan44 » Sat Jan 27, 2018 7:46 pm
Thanks for the reply.
The original S-R2's have tape and the Ksyriums do not, but I have checked and there seems to be no holes on that side of the tubes (if you know what I mean).
Oh and can you patch and re-use a tube if its been inflated with the CO2 cartridge? Saw the powder puff out of the valve and wondered if it might stuff it?
Thanks again
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Re: Do you pump your tyre to the max psi? and my bad experience today
Postby foo on patrol » Sat Jan 27, 2018 8:12 pm
Thought that was obvious.fat and old wrote:Did your original wheels have rim tape? Do the Kysriums? Are they supposed to?
Oh, and Foo means no to the last two questions
Foo
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