Smaller Cranks and Fitting Chainsets

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TraceyW
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Smaller Cranks and Fitting Chainsets

Postby TraceyW » 3 Apr 2016, 12:11pm

Hi

After about a 30 year layoff I have got myself another bike and am struggling to regain any level of fitness. However, this is not helped by cranks of 170mm (I'm only 5'5"). I find that pedaling is awkward and its putting a great strain on my knees and and hips and is likely to cause me give up any effort toward gaining fitness.

My bike is a second-hand Raleigh Pioneer 160 with 170mm cranks and I've been searching for 150mm or 155mm cranks as these lengths are likely the ones I need. I've found a few that may do the job although most of them are really rather cheap (around £20 or less) and sound too cheap to be any good. I DO know there is a Raleigh 150mm triple (RBR606) available at around £21 from Amazon - BUT - there is just one review of it and it is dreadful and in this instance could have severely compromised safety. So, does anyone have experience of this chainset and if so what sort of experience have you had? Has it been positive or is the chainset really to be avoided? Apart from this, is £20 really worth paying or should I try to go a bit higher?

I would also like to fit the chainset myself. However, I believe this may affect the chain and the setting up of the front derailleur due to smaller chainrings. Can any one advise me on this please (I'm not after procedures)?

A lot of questions I know but the alternative is to get a dealer to do the work but I am trying to keep costs down as much as possible. Any help would be most appreciated. Many thanks.

Tracey

Vorpal
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Re: Smaller Cranks and Fitting Chainsets

Postby Vorpal » 3 Apr 2016, 1:48pm

Honestly, I would just buy some cranks in the right size, and your preferred colour. You don't need to pay more than £20. (The ones on your bike are probably £8 ones)


It's possible that SJS Cycles or someone would have something a bit sturdier. Do you know what kind of cranks they are, or could you post pictures?

If nothing else, this company makes custom ones http://zinncycles.com/Zinn/index.php/custom-cranks

Does your bike currently have a triple, or would you also need to replace the shifters and derrailleur? If you bike has a triple, how many teeth are on each ring of your current triple, and the new one you are considering? We will need that kind of information to advise. In general, if you are not replacing like with like, some adjectments will be required.
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TraceyW
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Re: Smaller Cranks and Fitting Chainsets

Postby TraceyW » 3 Apr 2016, 2:45pm

Hi Vorpal

Sorry for the lack of info. My bike has a triple chainset with 48/38/28 chain rings. Assuming I were to go with the replacement Raleigh chainset (for example), this would have 42/32/22 chain rings. I've also seen others with 42/34/24. So yes, I intend sticking with 21 gears. However, this would make the chain rings slightly smaller than those currently fitted and I'm wondering what implications this would have on the chain length and the setting up of the front derailleur or will it be so small a change as to not be noticeable. As I say I'm just after what needs to be done rather than the procedure as I have some idea of that.

SJS do have something that would do - but no chain rings - but at £55 the cranks are rather more than I really want to pay and from what you say, its hardly worth it. I'd appreciate your comments please. Thank you very much.

Tracey

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531colin
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Re: Smaller Cranks and Fitting Chainsets

Postby 531colin » 3 Apr 2016, 4:25pm

You will need to replace the bottom bracket bearing as well as the chainset. You will need to adjust the gears. If the chain and cassette are worn, its not worth putting a worn chain on a new chainset, so that means new chain and cassette, and adjust everything. You will not be able to remove the existing pedals, cranks, or bottom bracket bearing without specialist tools, and even with tools these jobs can be difficult. The parts are not greased on assembly, and may not have been disturbed since, corrosion is almost guaranteed.
What makes you think your difficulties are anything to do with crank length? 170mm is not an unusual crank for people 5' 5" to ride. Some stretching and flexibility work are more likely to help than randomly changing crank length.

Mark1978
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Re: Smaller Cranks and Fitting Chainsets

Postby Mark1978 » 3 Apr 2016, 4:27pm

I'm 5'6" and went from 170mm to 165mm and it does help but I'm not sure I'd want to go shorter. The advantage of 165mm is that it's readily available. In my case it was just a straight swap pull out the old crank and chainset and fit the new one.

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gaz
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Re: Smaller Cranks and Fitting Chainsets

Postby gaz » 3 Apr 2016, 5:03pm

Subject to all the caveats already applied by 531Colin and otheres above, Spa offer the Stronglight Impact Kid in 150/155mm. It's a 44-34 double, 110BCD.
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DaveP
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Re: Smaller Cranks and Fitting Chainsets

Postby DaveP » 3 Apr 2016, 6:05pm

I had no idea how poorly the cycle trade serves people of smaller stature - until I had a quick rummage through my usual suspects to see if I could help. Can't even search by crank length in most cases.
I found and read the review of the Raleigh crank set. TBH it left me wondering if the reviewer had installed them incorrectly and then used the bike for jumping or some such - but I also found a review of another Raleigh crankset where the crank bent in its first week. I don't think I would buy one of these, at least not from this source.
I did an Amazon search for "chainset 150mm" which produced a couple of Suntour sets for twenty odd quid. Not high end but the brand is generally considered serviceable. They were both 42, 34, 24 though, and as Colin said, an apparently small change like this could be quite far reaching. I'm all in favour of buying tools and maintaining your own bike, but the cost of the tools required to tackle this yourself could compare to a bike shop labour charge.
Is it possible for you to borrow any bikes to try out say 160 or 165 cranks? It might not sound like a big change, but it doesn't always need to be, and there would certainly be a bigger selection of gearing available.
Trying to retain enough fitness to grow old disgracefully...

rualexander
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Re: Smaller Cranks and Fitting Chainsets

Postby rualexander » 3 Apr 2016, 6:28pm

Spa Cycles own chainsets and cranksets ar good quality and availabke in sizes from 160mm and up.
http://www.spacycles.co.uk/products.php ... 0s109p2000
http://www.spacycles.co.uk/products.php ... 0s109p2003

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531colin
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Re: Smaller Cranks and Fitting Chainsets

Postby 531colin » 3 Apr 2016, 6:45pm

Image

This is one of my volunteer bike testers........height "five feet and no inches" she tells me.......perfectly happy on 165mm cranks
Somebody 5' 5" tall with normal mobility doesn't need child-size cranks.

Tracey....how do you set your saddle height? If you go here http://wheel-easy.org.uk/ride-calendar.html you can download "Bike set up" which will give you a start.

andrewjoseph
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Re: Smaller Cranks and Fitting Chainsets

Postby andrewjoseph » 3 Apr 2016, 6:56pm

my wife is 5' 2" and rides a 165mm on the road and 170 on mtb.
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gregoryoftours
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Re: Smaller Cranks and Fitting Chainsets

Postby gregoryoftours » 3 Apr 2016, 7:25pm

165mm cranks should be ideal for someone of 5'5" unless you have unusually short legs for your height, and like others have said, the choice is pretty good for decent quality cranks in this length.

TraceyW
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Re: Smaller Cranks and Fitting Chainsets

Postby TraceyW » 3 Apr 2016, 10:08pm

Hi

Thanks for your replies.

Colin: It feels like you are criticising me for wanting shorter cranks. However, just because others of the same height as me can manage with 170mm cranks, it does NOT mean that everyone can. I still reserve my right to look for shorter cranks. In fact all my reading on the web indicates that more and more people are moving to shorter cranks -- and winning events!!! I have lookede long and hard at getting my riding position correct and I think I've got it just about right. Nevertheless, I will have a look at the document you suggested, thanks.

I am fully aware of the risks of replacing a chainset and fitting an old, possibly worn chain and I'm thinking about it and trying to learn how its done. However, since I intend to get a chainset which matches up with the BB I already have I don't really understand why I need a new BB! As I see it I should only need a pair of 150/155 cranks, a compatible replacement freewheel, a chain and the special tools.

Its just occurred to me that there is one small bit but perhaps important info I haven't provided. Yes, I am 5'5" (I've literally shrunk 1.5" since 1974) but the fact is I have very short legs with a correspondingly longer body. I think my inseam is in the region of 27.5" (approx 70cm) and I think its this that is causing my discomfort.

Mark: In my searching on the web I've found quite a few sites which state that shorter cranks are becoming more popular including the serious sports cyclists (don't know about the road racers). Apparently they are doing very well if not better with the shorter cranks than with the standard long ones.

To all respondents: Thank you very much for your responses but I think I shall see about moving to 150/155 cranks. Someone mentioned Suntour as being a respected make but as far as I can make out even those are Raleigh products. At least, I found one product on the Raleigh site being described as Raleigh Suntour.

My husband and I had reckoned about £70 to get a dealer to just change the cranks for 150/155 but I reckon it might be possible to get most of what Colin said I'd need to change (less the BB) for about the same cost. I really have to check the chain wear as yet and also have a closer look at the freewheel.

Dave: I had similar thoughts myself about the guy who left the review particularly as he made no comment regarding tackling Raleigh about it. Most odd. Presumably Raleigh have sold loads of those chainsets.

Anyway, thank you all for your responses. It may be a while before I'm able to sort anything out but I will try and report back.

Tracey

Vorpal
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Re: Smaller Cranks and Fitting Chainsets

Postby Vorpal » 3 Apr 2016, 11:32pm

TraceyW wrote:After about a 30 year layoff I have got myself another bike and am struggling to regain any level of fitness. However, this is not helped by cranks of 170mm (I'm only 5'5"). I find that pedaling is awkward and its putting a great strain on my knees and and hips and is likely to cause me give up any effort toward gaining fitness.

Are you certain that the bike is set-up correctly for you? If your hips are uncomfortable, maybe your saddle is a bit high? It may be worth lowering it and seeing if that helps.

Your knee should be slightly bent at the bottom of the pedal stroke.
“In some ways, it is easier to be a dissident, for then one is without responsibility.”
― Nelson Mandela, Long Walk to Freedom

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DaveP
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Re: Smaller Cranks and Fitting Chainsets

Postby DaveP » 4 Apr 2016, 9:00am

I thought about this yesterday, but wasn't sure if it was a good idea - crank shorteners. Usually encountered as a means of permitting children to pedal on a tandem. Please don't take offense :) I was just trying to think out of the box for a while.
Anyhow, I was surprised at how expensive they were, in general - except for these: http://www.sjscycles.co.uk/cyclo-crank- ... -prod3582/ Do note the comment about alloy cranks I don't know what that entails - I imagine something gets a file taken to it, but whether its the crank or the adaptor...? If no one comes forward a phone call to SJS might be the way to go.
As an approach I think its as ugly as sin, not something I would want to live with - but it might be a fairly cheap way to try out 150 mm cranks.
Trying to retain enough fitness to grow old disgracefully...

andrewjoseph
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Re: Smaller Cranks and Fitting Chainsets

Postby andrewjoseph » 4 Apr 2016, 9:09am

TraceyW, my wife has exactly the same inseam as you 27.5". as said above she has 165 on the road bike, 170 on the mtb.

spa do a triple for about £20. my wife has 24-34-48 chainset with ultegra 6703 shifters
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