Do you pump your tyre to the max psi? and my bad experience today

fauziozi
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Do you pump your tyre to the max psi? and my bad experience today

Postby fauziozi » Thu Jan 18, 2018 9:13 pm

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.

I always pump the tyre to the max as suggested by the bike shop to minimise chances of puncture, and I just pumped it again this morning until the needle is right at the 80psi mark. But the riding experience was bad, it was more bumpy than usual. But what made it dangerous was the tyre avoid obstacles like a plague, I could hit a small rock in front of me or even just a little crack on the road -- and it threw my ride sideways like never before.

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. Lucky I was going slowly so I could immediately landed my foot, there wasn't many cars, and as it was in the middle of brunswick rd (i.e. crowded street) the cars were moving slowly.

I'm sure it was because of an over-inflated tyre, but please let me know if it could be something else. I've ridden through this route couple of times before and never had this kind of experience, so cycling style may not be it.

Also, its only been 2 months since I bought the bike and the gear-switching performance has declined quite a lot. When it was brand new, it switched gears right away (except when riding uphill where sometimes it failed to switch), but in today's ride -- sometimes it took 6-8 full pedal for the gear to switch. Is it already time for a tune-up?

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Re: Do you pump your tyre to the max psi? and my bad experience today

Postby BJL » Thu Jan 18, 2018 9:27 pm

You made a couple of mistakes. First of all, to make any comments about your tyre pressure, you need to tell us what size tyres you're running and how much you weigh. Pumping them up to their maximum isn't the correct way to determine proper pressure.

Secondly, you should always cross tram tracks at 90 degrees or as close as possible to. I always do a hook turn at intersections with tram tracks.

Edit - just read the bit about gear changing. New gear cables will initially 'stretch'. They will need to be adjusted after a few rides.

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Re: Do you pump your tyre to the max psi? and my bad experience today

Postby DavidS » Thu Jan 18, 2018 9:55 pm

What BJL said, and I'll add that I run 700 x 28 tyres with a maximum psi of around 100 psi and generally pump them to about 85-90 psi. Tyres sometimes skip when they hit an object, especially when pumped up hard, not unusual.

Details of the bike and tyres would be good. New cables do stretch but you should be able to adjust them on the derraileur or, if you are on a flat bar, the shifters often have an adjusing screw.

Tram tracks can be a challenge, never noticed if this is more of an issue with tyres pumped up to the max.

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fauziozi
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Re: Do you pump your tyre to the max psi? and my bad experience today

Postby fauziozi » Thu Jan 18, 2018 10:24 pm

Good to see I have so much to learn! otherwise I'd be stuck with this awful experience.

Not sure what the tyres size are, on the side its brand is a Schwalbe active roadcruiser. And it has this writings embossed 32-622 128 x 1.30 - 700 x32CI HS 377.

Bicycle is Marin Fairfax SC 1. Frame size: S

I'm 87kg. Down from 89kg since the past 2 weeks because of cycling!

I'm still not 100% sure with roadrules. As of now, I am just following a simple rule of: if there is a bike path, take it. If there is none, get on the far left side of the road and follow the normal road rules as if I am driving a car.

This has caused issues though, such as when attempting to turning right on a round about, or when its a fork (image: https://www.google.com.au/maps/@-37.7817833,145.0247243,3a,75y,109.03h,78.58t/am=t/data=!3m10!1e1!3m8!1sZtRgdgPALVOIMbQmo0glXw!2e0!6s%2F%2Fgeo0.ggpht.com%2Fcbk%3Fcb_client%3Dmaps_sv.tactile%26output%3Dthumbnail%26thumb%3D2%26panoid%3DZtRgdgPALVOIMbQmo0glXw%26w%3D203%26h%3D100%26yaw%3D78%26pitch%3D0%26thumbfov%3D114%26ll%3D-37.781828,145.024825!7i13312!8i6656!9m2!1b1!2i18. For this issue, I pretty much just look at what other cyclist are doing and follow them (which is what I did with turning right even with the tram track).

2 weeks ago, when there is a tram track when I needed to turn right; I actually did a hook turn as well. Though as no one else did it, and I had that "look" from everyone since I'm positioned in front of the adjacent traffic light, I decided to just take over the right lane of the road and make the right turn as if I'm driving a car.

Regarding the adjustment to derraileur, I'm sure I can find the video for it in youtube. Though it'd be great if you have it bookmarked somewhere since I won't know exactly what I'm looking for and will need to watch a couple of videos to know if its what I'm looking for. Mine is a flat bar :)

Thanks heaps! u guys are awesome

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Re: Do you pump your tyre to the max psi? and my bad experience today

Postby Tim » Thu Jan 18, 2018 11:01 pm

Correct me if I'm wrong but I think Melbourne was extremely hot today.
40+℃ is hot enough to burst already highly inflated tyres, it's happened to me. They cool under motion but heat up when stationary and go off like a double-barrelled shotgun.
It's also hot enough for steel cables to expand and lengthen, effectively throwing out delicate cable tension adjustment and messing up gear changes.
NEVER ride over tram tracks at an acute angle.

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Re: Do you pump your tyre to the max psi? and my bad experience today

Postby trailgumby » Thu Jan 18, 2018 11:04 pm

You're doing the right thing by the road rules, hard to go wrong with that approach. Two tips: you don;t *need* to signal left turns, but should whenever possible. You can also overtake on the left, but let an experienced voice impart some wisdom: never do so when it's a truck or bus, or if the left indicator is going.

The advice re: tram tracks is sound - always at 90 degrees or as close as you can manage. Being a mountain biker I treat them like wet tree roots and loft the wheels over them, but that is an advanced strategy. You should google "bicycle hook turn" - it's a sound, conservative strategy for making right turns at busy intersections generally, not just when train or tram tracks are involved.

On tyre pressure, yes you're too high. 70psi rear / 65psi front would be as high as I'd go, and probably lower. 80-ish is what I run on my roadie with 25mm tyres at not much less than your current weight. Your tyres are nominally 32mm wide.

Running high pressures is uncomfortable, no faster, makes your bike skittish (as you've found) and longer term you will bust spokes from road shock.

Does that help?

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Re: Do you pump your tyre to the max psi? and my bad experience today

Postby fauziozi » Thu Jan 18, 2018 11:21 pm

Tim
Yes, it was 40degrees today in Melbourne. I was breathing in hot air whilst cycling, it was hell.
If what you're saying is common, I suppose I got lucky the tyre isn't damaged then.

With the heat messing up the cables and gearing, will it go back to what it was when it cools down? or do I need to manually tinker with it?

Wasn't intentional with the acute angle on a tram track, and especially with the tyre I had today.

trailgumby
well, with that said -- I'm now throwing away the bike shop's advice to have my bike fully pumped at max psi. Will go for a ride in the next 2 weeks, decreasing psi by 5 every 3 days to find my comfort zone.

will also look at that special skill "bicycle hook turn"

Thanks guys.

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Re: Do you pump your tyre to the max psi? and my bad experience today

Postby BJL » Thu Jan 18, 2018 11:24 pm

Okay, let's start with your tyres. I'm 100kgs (on a good day) and I run about 80psi on my hybrid running 700-28. So with 32's, you could probably lower that to 70 at your weight ( but I'll leave it to others to give a more correct answer here)

Hook turns are legal for cyclists in Victoria everywhere unless there is a sign prohibiting hook turns for cyclists. I do hook turns everywhere I can (I don't care what looks I get). Firstly, they're often faster, and secondly, hook turns keep you to the left of the road out of the way. Hook turns are also legal on roundabouts but cyclists MUST give way to traffic exiting the roundabout. So it'll take multiple little 'jumps' but if it's busy, but then self preservation takes precedence.And thirdly, I have a neck injury that restricts my neck movement so it's safer for me anyway. (I might be a bit aggressive towards idiot motorists on these forums, but I look after myself and ride according to my abilities).

For your gear problem. I didn't want to go into detail as there are many different types of derailleurs, but for the most part, you'll have a barrel 'adjuster' where the cable enters the rear derailleur. The idea is to lengthen or shorten the 'outer' to compensate for the stretch of of the inner. This is done by winding the adjuster out (anti clockwise) So the rule of thumb is, looking from the rear of the bike, if you have trouble shifting to the bigger cogs (to the left), turn the adjuster 1/4 turn to the left (anticlockwise). And vice versa. Then re-check. I find you need to shift through the entire range at least once before you know if it's enough or not. And riding with it under load is different to having the bike on a stand or just moving the pedals by hand. You'll probably need to ride it for a bit and adjust it along the way.

It's much the same for the front except that front derailleurs don't usually incorporate a barrel adjuster and hence (like me) you'll be relying on a barrel adjuster somewhere else, like on the down tube.

It can be hard to visualize at first (And trust me I know. I don't understand anything without seeing an animation of some sort!) but once you've got your head around it, it's really quite simple.

And by the way, it your chain gets 'thrown' either way, you'll need to adjust the 'limit' screws. If you've got Shimano gear, you can download to tech documents from:

http://si.shimano.com/#/

I hope this helps.

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Re: Do you pump your tyre to the max psi? and my bad experience today

Postby fauziozi » Thu Jan 18, 2018 11:53 pm

Thanks BPL, I'll look it up.

Any tips on turning right on peel st / duddley st near the Victoria market?
google map: https://www.google.com.au/maps/@-37.808 ... 312!8i6656

can't do hook turn here because there's no incoming traffic from the left. And things get really busy there with the roundabout.

For the next time, I am planning to just cross the road using the pedestrian crossing about 100m behind the intersection. But then, after crossing this I will be riding at the pedestrian path for a while (and going against the traffic)

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Re: Do you pump your tyre to the max psi? and my bad experience today

Postby human909 » Fri Jan 19, 2018 12:53 am

The bits about crossing tram tracks at 90 degrees or close to is a little bit of an overreaction. I and plenty of other Melbourne cyclists happily cross them at angles closer to 20 or possibly even 10 degrees. Afterall how else do you change into the tram lane when riding parallel to tram tracks?

Sure exercise caution, but that doesn't mean you can't cross the tracks.

fauziozi wrote:Any tips on turning right on peel st / duddley st near the Victoria market?

Position yourself in the right turn lane and turn right like any other vehicle. I used to regularly make right turns there, it not different from driving a car.

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Re: Do you pump your tyre to the max psi? and my bad experience today

Postby fat and old » Fri Jan 19, 2018 5:47 am

human909 wrote:The bits about crossing tram tracks at 90 degrees or close to is a little bit of an overreaction. I and plenty of other Melbourne cyclists happily cross them at angles closer to 20 or possibly even 10 degrees.



If it's wet next week as per forecast, don't do this! Tram tracks (any steel really) are treacherous when wet. Stick with what you're doing until you build up some more experience/confidence/fear of falling.

Re Peel/Dudley. If you're not comfy, go along Victoria (West bound) until Capel then down that to Dudley. Nice bike lane, bike crossing at Dudley.

https://www.google.com.au/maps/@-37.807 ... a=!3m1!1e3

For what it's worth as you seem to be using the normal route that a car would take...if you're near the Chandler Hwy then easy access to Main Yarra Trail (at The Boulevard) which eventually becomes Capital City Trail and runs straight into Docklands if you don't want to use the road at all. These will show on Google earth, a w/e ride to suss it out maybe.

Yeah, yesty was stinking. Props for riding in that. At least you didn't have a straight headwind. That sucked. :lol:

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Re: Do you pump your tyre to the max psi? and my bad experience today

Postby Kev365428 » Fri Jan 19, 2018 6:51 am

Might as well throw my 2c worth in here.

I'm 91kg and run 700x23 tyres. I infate mine to 115psi.
Anything less than this and the bike feels like it's squirming about on the road surface.

I guess it comes down to personal preferences. I prefer the feel of a firm road tyre under me. Soft tyres make me paranoid about cornering, except in the wet when I drop about 10psi.

I would put too much into the heat of the day affecting your cables. There is no way they will grow enough to affect gear changes just because it's a hot day.
As others have suggested, new cables stretch after a period, and will require adjusting. Google is your friend if you need info/video's to assist.

Keeping up the riding will see that weight drop continue, so don't stop.

Kev.

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Re: Do you pump your tyre to the max psi? and my bad experience today

Postby bychosis » Fri Jan 19, 2018 7:10 am

Your bike shop might (should) help you with adjusting the gears as a free service on a new bike, but it’s worth learning how to do it yourself.

From the tyre size info you provided 700x32c is the bit that gives you the ‘common’ sizing info used in Aus. 700c rim size (the c is not for cm) which is the most common road bike size, and 32 for 32mm wide.

Pumping to the max tyre pressure on the tyre is not the right way to do it. Typically a ‘normal’ sized person should be able to start at least 10% under the max. It can take some trial and error, but try dropping 10psi for a short ride and see how it goes.
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Re: Do you pump your tyre to the max psi? and my bad experience today

Postby Thoglette » Fri Jan 19, 2018 7:53 am

Kev365428 wrote:I'm 91kg and run 700x23 tyres. I infate mine to 115psi.
Anything less than this and the bike feels like it's squirming about on the road surface.


There's a bunch of charts out on the interweb like the one below to set up for for 15% drop
Image
(from Jan Heine's blog )

At 90kg your rear (c. 50kg) is "about right" but the front could drop 10psi.
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Re: Do you pump your tyre to the max psi? and my bad experience today

Postby bychosis » Fri Jan 19, 2018 8:36 am

^ for the OP at lets say 90kg to allow for some clothes and a drink (and to make the maths easier) Front weight 40kg, rear 50kg (rounding). 32mm tyres: just over 50psi on the front and around 63psi on the rear.
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Re: Do you pump your tyre to the max psi? and my bad experience today

Postby human909 » Fri Jan 19, 2018 11:40 am

fat and old wrote:If it's wet next week as per forecast, don't do this! Tram tracks (any steel really) are treacherous when wet. Stick with what you're doing until you build up some more experience/confidence/fear of falling.


I agree that people should stick within your comfort zones.

I disagree that tram tracks should be avoided when wet. They just need to be ridden to the conditions like anything else in driving or riding. AKA don't expect them to have grip. So don't corner tightly on them. That doesn't mean you don't turn across them, you just need to straighten your line before you cross them and tighten your line afterwards.

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Re: Do you pump your tyre to the max psi? and my bad experience today

Postby ColinOldnCranky » Fri Jan 19, 2018 3:35 pm

I rode around 150,000-200,000km in another era, CoMo frames etc, with 1" tyres pumped to a less than solid-rubber hardness. I think I had maybe two, maybe three times I got snake-eye punctures from unexpected obstacles. And paths and roads were nowhere near as smooth and predictable as they are now.

These days whenever I press the tyre on someone's flash CF bikethey may as well be solid rubber, albeit a lot lighter. Consistent with the OP, I wonder what good it is to have the tyres pumped to rock-hard and also wonder what it does in the long-run to the bike. What is it with high pressures, a pissing contest?

Then again maybe long-run is not of consequence to the owners of these highly exotic and stratospherically priced frames. Anecdotally is seems that people turn them over according to the change of seasons and as the market finds a newly favoured colour or as brands drop from favour. However it must still be a bit less comfortable for the rider.

I eventually had to give up riding as an elbow failed, an outcome at least contributed to by the pounding they got from the transmission of road to the drops. I doubt that I would have got as far as I did if I had pumped my tyres to the extent that so many do these days.
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Re: Do you pump your tyre to the max psi? and my bad experience today

Postby ColinOldnCranky » Fri Jan 19, 2018 3:42 pm

Train tracks are ALWAYS chancy. As suggested already, you must go at right angles. On wet roads it's best to hop off at tracks but we never do so slow right down. You need to also be little wary of grates on roads but if you ride regular routes you get to know where the serious hazards are.

A wider tyre is a clever option if you can't otherwise reduce the pressure to something comfortable. Let others be uber-cool on tyres as thin as pram chord, you just want to get to where you are going.
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Re: Do you pump your tyre to the max psi? and my bad experience today

Postby Philistine » Sat Jan 20, 2018 3:54 pm

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.

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Re: Do you pump your tyre to the max psi? and my bad experience today

Postby Thoglette » Sat Jan 20, 2018 4:13 pm

fauziozi wrote:Also, its only been 2 months since I bought the bike and the gear-switching performance has declined quite a lot. When it was brand new, it switched gears right away (except when riding uphill where sometimes it failed to switch), but in today's ride -- sometimes it took 6-8 full pedal for the gear to switch. Is it already time for a tune-up?


New cables "stretch" as they bed in. This is the most likely cause. In which case you need to tweek the gear shift cable adjuster barrel to tighten the cable just a bit.

The other possibility is that you've bent something (if you have a deraileur gears). This only happens if you drop or otherwise whack the bike HARD.

In any case read what Sheldon has to say about derailleur gears. The picture below shows the adjusting barrel.

Image (From Sheldon, of course)
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Re: Do you pump your tyre to the max psi? and my bad experience today

Postby fauziozi » Sat Jan 20, 2018 6:48 pm

Thanks for the picture. I'll play around with it :)

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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 20, 2018 7:56 pm

Never taken any notice of these so called graphs for what pressure that you should run and not about to start now. :roll: Pump them up to a pressure that feels good for you. :wink:

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Re: Do you pump your tyre to the max psi? and my bad experience today

Postby madmacca » Sun Jan 21, 2018 10:41 am

foo on patrol wrote:Never taken any notice of these so called graphs for what pressure that you should run and not about to start now. :roll: Pump them up to a pressure that feels good for you. :wink:

Foo


I think even St Jan would say that you should adjust tyre pressure based on experience. Nevertheless, the chart makes a good starting point for newbies, or when changing tyre sizes.

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Re: Do you pump your tyre to the max psi? and my bad experience today

Postby sammutd88 » Sun Jan 21, 2018 11:55 am

fat and old wrote:
human909 wrote:The bits about crossing tram tracks at 90 degrees or close to is a little bit of an overreaction. I and plenty of other Melbourne cyclists happily cross them at angles closer to 20 or possibly even 10 degrees.



If it's wet next week as per forecast, don't do this! Tram tracks (any steel really) are treacherous when wet. Stick with what you're doing until you build up some more experience/confidence/fear of falling.

Re Peel/Dudley. If you're not comfy, go along Victoria (West bound) until Capel then down that to Dudley. Nice bike lane, bike crossing at Dudley.

https://www.google.com.au/maps/@-37.807 ... a=!3m1!1e3

For what it's worth as you seem to be using the normal route that a car would take...if you're near the Chandler Hwy then easy access to Main Yarra Trail (at The Boulevard) which eventually becomes Capital City Trail and runs straight into Docklands if you don't want to use the road at all. These will show on Google earth, a w/e ride to suss it out maybe.

Yeah, yesty was stinking. Props for riding in that. At least you didn't have a straight headwind. That sucked. :lol:


I agree with the above. Especially till you are 100% comfortable, take the trails. I take trails a lot on my road bike and I find it's so much quieter and less "stressful". Experiment with tyre pressure. For example, on 25c tyres I've found at 85kg's 90-95psi works best. 28c, 80-85psi is best. Also depends on rim width and other variables. Less pressure is not slower, is more comfortable and stresses the wheels a lot less. Just don't go so low that it affects handling or you get pinch flats.

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Re: Do you pump your tyre to the max psi? and my bad experience today

Postby kb » Sun Jan 21, 2018 12:32 pm

Tim wrote:Correct me if I'm wrong but I think Melbourne was extremely hot today.
40+℃ is hot enough to burst already highly inflated tyres, it's happened to me. They cool under motion but heat up when stationary and go off like a double-barrelled shotgun.
It's also hot enough for steel cables to expand and lengthen, effectively throwing out delicate cable tension adjustment and messing up gear changes.
NEVER ride over tram tracks at an acute angle.

Sometimes it’s hard to avoid and can be done safely but needs practice and a bit of technique with weight distribution and timing. Wouldn’t suggest experimenting during commutes.
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