Which Cassette?

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Which Cassette?

Postby darkpromenade » Sat Dec 15, 2007 6:57 am

The 7-speed cassette I have on my roadie is an 11-21, and with my 52/42 chain rings I find that hills are just impossible. How large should I go on the back? I can get 23, 26, 28, 30, 32 or 34 tooth large sprockets on a 7-speed cassette. I know it depends on the rider, but what ratios are other forum members using for climbs? I would be particularly interested in what Adelaide riders use in the Hills (Norton Summit, Greenhill Road, Eagle-on-the-Hill etc.)
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by BNA » Sat Dec 15, 2007 7:17 am

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Postby Deanj » Sat Dec 15, 2007 7:17 am

I ride with a 39-53 front and a 12-25 (10 speed rear). I'm up at Mt Barker so get my fair share of hills :D . I've not ridden up Greenhill (I'd imagine to be similar to Norton Summit) yet as my usual ride brings me down this and then I head up Eagle on the Hill, rode Norton Summit about 2 weeks ago and with this gearing I find neither hill a problem gearing wise. I'm usually happiest about 95-105 cadence an although I can't always get it on these climbs I'm usually in the 80's somewhere and at times a bit less. Theres a few hills about that I need to stand up on to get up but nothing thats unclimbable (I'm sure there is somewhere though). From Crafers up to Mount Lofty is a bit of a climb and I also find it ok for that. I am in top/bottom/first (whatever its called) gear though most of the time. There is a gear calculator somewhere in one of these posts I'll have a look.

Gear calculator
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Postby mikesbytes » Sat Dec 15, 2007 7:36 am

A 28 on the rear would give you a 25% (or is it 33%?) lower gear. Going past that will create holes in the gear range. However its an individual thing.

How high a top gear do you need? A lower top gear will help reduce the gaps.
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Postby Deanj » Sat Dec 15, 2007 7:49 am

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Big downhill is Greenhill Road from top of Mount Lofty
Big uphill is Eagle on the Hill
Last edited by Deanj on Sat Dec 15, 2007 4:33 pm, edited 1 time in total.
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Postby darkpromenade » Sat Dec 15, 2007 8:03 am

OK, from Sheldons website, needsapush rides a 39-25 (ratio 3.1) and I currently ride a 42-21 (ratio 4.0). A 42-28, as per mikes suggestion would be a ratio of 3.0, which would be about right.

I could afford to probably drop from an 11 to a 12 at the other end, but the run down Cross Road from the Eagle can be done pushing a big gear. I'm yet to do it on this bike though, so I'm not sure I'll need the 11.
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Postby europa » Sat Dec 15, 2007 9:02 am

Here we go again :D

My setup.

Chain rings - 26, 40, 52

Cassette (SRAM) - 11-12-14-16-18-21-24-28-32

I haven't tried Greenhill or the Eagle yet, but am climbing the big hills down here with a cadence of 90 and a comfortable HR - Greenhill would push that HR up.

No Mike, there aren't any holes in that set up. You do notice the jump from the 24 to the 28 but when you're reaching that low, that is usually a good thing. Having said that, I can understand why someone trying to maintain an even pace on the flat would prefer 1 tooth progressions.

The chainring progressions are smooth and very rarely require a double shift. There's no need to cross chain on this set up because of the sensible overlap between the rings. Having said that, it's also possible to just live on the middle ring if inclined.

It's a good, alround setup that allows me to run with the fastest (yes, I regularly use top though only downhill with these old legs) yet climb anything I face.

Were I to loose the granny, I'd still go with that rear cassette and chainring combination.

Now having gearing on a bike that allows me to loaf up hills, I can't see the point in killing yourself trying to climb with higher gearing.

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Postby toolonglegs » Sat Dec 15, 2007 9:25 am

why dont you put a 39 or 38 on the front or wont it take one?,
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Postby Bnej » Sat Dec 15, 2007 11:49 am

europa wrote:Now having gearing on a bike that allows me to loaf up hills, I can't see the point in killing yourself trying to climb with higher gearing.


To go faster! Also to use short cage deraileurs and lighter road cassettes.
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Postby europa » Sat Dec 15, 2007 12:02 pm

Bnej wrote:To go faster!


I'll pay that one, but to me, the speed is only of academic interest and I sometimes wonder how important it needs to be to other riders.

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Postby Jeremy » Sat Dec 15, 2007 12:46 pm

I run a 39/52 and 11-23.......i can get up hills now, but it's taken a while to get there.

I guess it's a matter of how hard you want to work to get up the hill....if you are like Richard and have no interest in how long it takes you to get up the hill, then find the lowest gearing you can.

I'm more competitive than that, so i figured that if others can manage to power up the hills using very similar gearing, at a much faster rate than me, then i had to HTFU and train :)

My dad had identical gearing to me but really struggled in the hills so chose to drop to a 11-25 cassette.....he found it slightly easier, but now i'm even faster up the hills ;)
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Postby darkpromenade » Sat Dec 15, 2007 1:47 pm

Jeremy wrote:I run a 39/52 and 11-23.......i can get up hills now, but it's taken a while to get there.


Your 39/23 would be equivalent to a 42/25.... so thats a vote for a 25 and a vote for a 28.

Going for a smaller chainring is a good idea, but I'm using late '80s biopace chainrings and I havn't seen one smaller than a 42.

I'm somewhere between a loafer and a "pusher"! I'm not one to simply cruise around, but I also know I have to take it a little easier on my longer rides. My riding is all about overall cardiovascular fitness, so working in that 60-70% max HR range is important, rather than hammering all the time. Having said that, I'm a sucker if I see someone ahead of me on the road...... I have to try and catch them!
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Postby LuckyPierre » Sat Dec 15, 2007 1:58 pm

You'll probably find that the 7-speed cassettes with anything more than 26 teeth are really mtb cassettes and your rear derailleur won't accomodate them. Drop down to a 39 tooth small chain ring and set yourself up with a 12-26 (or 11-26 if you want to push it on the flats) rear cassette.
Don't worry about the 'bio-pace' bit - it was a pretty short-lived design (yes, I know that a couple of obscure manufacturers still do something that's just different enought to avoid any patent issues).
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Postby darkpromenade » Sat Dec 15, 2007 2:11 pm

There's an explanation about that on ebay from a guy selling a 12-28. Apparently to use a 12-28 7 -speed cassette you can't have more than 12T difference in your chain rings, which means at 42/52 I should be fine. Thats a big should.

The whole Biopace thing is more to do with the fact that thats what the bike originally came with..... definitely more about the heart than the head...... trying to keep it as it was, circa 1990.

If I thought I could push a 42/26 up the hills I'd go with that....... I might have to go and check what the Rockhopper has, as I could cruise up the hills on the middle chain ring and the smallest rear cog without too much of a problem.

brb!
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Postby darkpromenade » Sat Dec 15, 2007 2:26 pm

OK, i'm in trouble.

I climbed the hills on the Rockhopper using a 32T chain ring and a 32 or 26 rear sprocket. Thats a 2.0 or a 2.5 ratio. Even with a rear 28 I'm only at 3.0. Now the roadie weighs at least 4kg less than the Rockhopper and has much less rolling resistance but it seems a lot to make up.

Smaller chain ring is looking like the only choice. Hmmmmmmmm.




On another topic, I'm about to go for a ride! :)
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Postby Bnej » Sat Dec 15, 2007 4:29 pm

39/26 is a good bottom gear for most people. 34/50 crankset if you are having trouble keeping a decent cadence with the 39. If that's still not good enough you can go to a triple. I have 30/39/50, and do 99% of my riding on the 39 and 50 but sometimes when you're really tired it's nice to have a gear you can take a break in.

If you want the same effect as the biopace rings I believe Rotor make elliptical chain rings that can be set up pretty much the same.

BTW I find I can push a 39F/26R on the road bike on similar gradients that I use a 34F/30R or so on my mountain bike - weight difference is similar FWIW.
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Postby darkpromenade » Sat Dec 15, 2007 7:02 pm

39/26 is a ration of 3.o from sheldonbrown.com, which seems to be what people are saying.

34/30 is 2.3, similar to what I was pushing on the Rockhopper........

So again, maybe I'll be alright at 28 with the 42T chain ring........

Anyone got a 12-28 7 speed Hyperglide cassette they want to get rid of? :)

p.s. the ride was good....... head wind on the way back along Port Road was hard work. 49.83km (AT) 30.1km/h
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Postby CoffeeNut » Sat Dec 15, 2007 8:39 pm

53/39 and 11/25

When I first started, I was finding some of the hills a pain and was thinking about a 27 for the back - but as I have got stronger I don't need to do this now. Don't change too far !!
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Which Cassette?

Postby silverlight » Thu Dec 27, 2007 8:19 pm

I too am currently running an 11-23 on an 53/39 and its all about training, it does take time though. Like Jeremy I looked at what others were riding and tried to follow their example and say if they can so can i. It just depends what you want out of the riding is it more cardio or power or both. I want a bit more strength/power in my legs and although i know i could inflict less torture on myself i decide to stick with what i have, yes im still out of breath but its a great feeling conquering the corkscrew (off gorge rd.) or skye (to the lookout) (both in adelaide) when you get to the top. When you get really good you can try and beat jack bobridge time of 11mins 50secs up norton summit. It does take time but each ride does get easier and you will soon reap the awards of self accomplishment. :)
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Postby Jeremy » Thu Dec 27, 2007 8:38 pm

Hahaha, funny you should mention corkscrew......i tackled it for the first time on monday, and it was alot tougher than the eagle, or gorge rd.....

Dad called it, and said he couldn't go any further, and being just the two of us, we turned back down (damn it was hard on brakes too :) ) I looked up later how far we'd got, and were pretty close to completing it :(

I was certainly struggling too though.....and realised that all hills are not created equally......i was actually meaning to come back to this thread and say i was considering adding a bigger cog :oops:
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Postby Deanj » Thu Dec 27, 2007 8:55 pm

What road is corkscrew? I'm looking for a new route for Sunday!
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Postby Jeremy » Thu Dec 27, 2007 9:19 pm

It's actually called corkscrew rd......go to www.whereis.com and put in corkscrew rd Montacute......that'll give you a rough idea......

It's quite a skinny rd with an old faded sign leading off the right hand side of gorge rd as you start to hit the hills.....easy to miss if ur not looking for it ;)
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Postby Deanj » Thu Dec 27, 2007 9:27 pm

Got it, I looked on bikely but didn't follow Gorge Rd far enough. I'll draw me a ride up for the weekend and hopefully give it a go!
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Postby europa » Thu Dec 27, 2007 11:30 pm

The Gorge Rd and the Corkscrew are both very narrow and very twisty. They are the sorts of roads where drivers come flying up behind you, have to slow down to a crawl and have nowhere safe to pass. These are the sorts of circumstances that are very unsafe to all concerned and which aren't helping the attitude of drivers towards us in the slightest (one of the largest causes of complaint on the radio). Yes, we deserve to be able to ride where we want to, but the Gorge is one road I won't ride up, particularly in any sort of group, because it just isn't safe, and not helped by groups of riders who don't give a stuff about the other road users. Sorry, co-operation is the only way to make many of the hills roads work and while some riders refuse to offer any, the impatient motorist won't play ball either (don't get me wrong, both are to blame).

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Postby sogood » Fri Dec 28, 2007 1:33 am

europa wrote:No Mike, there aren't any holes in that set up. You do notice the jump from the 24 to the 28..

Isn't that what a "hole" is? A noticeable jump from one cog to the next.
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Postby Deanj » Fri Dec 28, 2007 5:02 am

europa wrote:The Gorge Rd and the Corkscrew are both very narrow and very twisty. They are the sorts of roads where drivers come flying up behind you, have to slow down to a crawl and have nowhere safe to pass. These are the sorts of circumstances that are very unsafe to all concerned and which aren't helping the attitude of drivers towards us in the slightest (one of the largest causes of complaint on the radio). Yes, we deserve to be able to ride where we want to, but the Gorge is one road I won't ride up, particularly in any sort of group, because it just isn't safe, and not helped by groups of riders who don't give a stuff about the other road users. Sorry, co-operation is the only way to make many of the hills roads work and while some riders refuse to offer any, the impatient motorist won't play ball either (don't get me wrong, both are to blame).

Richard


I don't know that area too well at all, but have done Gorge road a couple of times on the motorbike. As you say, I wouldn't think of riding all the way along it. Not looked at my route there as I went straight to bed after, but, if I can't get there what I class as "safely" it wouldn't happen. This leaves me a little stuck at times coming up with routes from my place, and is the reason I stick to my regular 100 km loop, its low traffic and the roads have reasonable visibility. Do you take the straight 100-110 km roads out Strath way, or the slower, less visible roads of the hills?

Another problem with the Hills is the busiest time on the roads is the weekends. I've worked on a road all day Sunday and the traffic was a nightmare. Did the same stretch (within a few k's) midweek and traffic was at a guess around 10% of the weekend. This was another road I wouldn't ride all the way along but a busy cyclist route, Loebethal Road.

I don't mind riding down any of the hills into the city as your usually faster than cars, but all but once, I've come back up Eagle.
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