New bike broken
08-09-19, 12:10 PM
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New bike broken
Hi All
Bought a new bike and used it for a couple of weeks. It wasn't expensive but I've managed to strip the thread from the left crank arm and cross thread the right pedal. Such a donut.
It's a Marin LARKSPUR CS1 city. According to their web site I need a Shimano FC-TY301, 48/38/28T, Ring Guard 175mm ( bike is a large size )
I can't find this exact crankset anywhere ( too old ? ) to buy a replacement. I have a friend who can fit it.
Sorry about the noob question but any ideas what I can use instead ? There seem to be plenty of FC-TY501 sets around. Are these the same size ?
Thanks all in advance
wert
Bought a new bike and used it for a couple of weeks. It wasn't expensive but I've managed to strip the thread from the left crank arm and cross thread the right pedal. Such a donut.
It's a Marin LARKSPUR CS1 city. According to their web site I need a Shimano FC-TY301, 48/38/28T, Ring Guard 175mm ( bike is a large size )
I can't find this exact crankset anywhere ( too old ? ) to buy a replacement. I have a friend who can fit it.
Sorry about the noob question but any ideas what I can use instead ? There seem to be plenty of FC-TY501 sets around. Are these the same size ?
Thanks all in advance
wert
08-09-19, 12:27 PM
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You should be fine. As far as I can tell, both are "Square Taper".
Doing a swap like that, always plan on adjusting your front derailleur.
Be careful with right pedals having right threads, and left pedals having left threads.
Also note, there are a lot of used and NOS parts on E-Bay, and sometimes Amazon. You need your two crank arms to match in length, but they do come in 170mm and 175mm lengths (depending you your legs and preferences).
A crank puller tool will make getting the cranks off much easier.
https://www.amazon.com/Park-Tool-CCP...dp/B001VS1M20/
There are many generics, many without the handles. Or, you can go to a bike shop for assistance.
If you have loose bearings in the bottom bracket, this would be a good time to grease those. If they are sealed, then you're fine.
Doing a swap like that, always plan on adjusting your front derailleur.
Be careful with right pedals having right threads, and left pedals having left threads.
Also note, there are a lot of used and NOS parts on E-Bay, and sometimes Amazon. You need your two crank arms to match in length, but they do come in 170mm and 175mm lengths (depending you your legs and preferences).
A crank puller tool will make getting the cranks off much easier.
https://www.amazon.com/Park-Tool-CCP...dp/B001VS1M20/
There are many generics, many without the handles. Or, you can go to a bike shop for assistance.
If you have loose bearings in the bottom bracket, this would be a good time to grease those. If they are sealed, then you're fine.
08-09-19, 12:50 PM
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You can also have Heli-Coil or similar threaded inserts put in to repair the stripped threads stronger than original.
08-09-19, 12:57 PM
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This. If you have a machinist friend (or a cheap pro nearby) it can be done for not too much $$. Check for bike Co-Ops nearby too. Not many will have the Heli-Coil tools necessary but worth it to ask them.
08-09-19, 01:59 PM
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08-09-19, 02:24 PM
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Good suggestion jimc, but it looks to be out-of-stock. Last I looked, Random Bike Parts had quite a few reasonably priced cranks, and may have something compatible.
edit: here's a link......
https://www.randombikeparts.com/collections/cranks
(they also ship free, and I believe "save10" will get another 10% off).
This one might work....https://www.randombikeparts.com/coll...-42-34-24t-new
edit: here's a link......
https://www.randombikeparts.com/collections/cranks
(they also ship free, and I believe "save10" will get another 10% off).
This one might work....https://www.randombikeparts.com/coll...-42-34-24t-new
Last edited by Brocephus; 08-09-19 at 02:41 PM.
08-09-19, 02:32 PM
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If money is tight, one can also head to the local bike co-op/recyclery.
They should have the tools to remove the bad crank, and may have a box of replacement cranks available for a reasonable price.
Right and Left just have to be similar, but don't have to be the exact same brand/model. Same length, same bottom bracket mount & orientation, similar Q-Factor, and one is good to go.
They should have the tools to remove the bad crank, and may have a box of replacement cranks available for a reasonable price.
Right and Left just have to be similar, but don't have to be the exact same brand/model. Same length, same bottom bracket mount & orientation, similar Q-Factor, and one is good to go.
08-10-19, 03:26 AM
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Thanks so much for all the advice. I should have mentioned i'm based in the UK. I think the cheapest option is to swap out the whole crankset which I can replace for ~£30.00.
Is it possible to just replace the crank arms ? Are they all the same design i.e I can buy a 175mm generic arm and it will fit ?
w
Is it possible to just replace the crank arms ? Are they all the same design i.e I can buy a 175mm generic arm and it will fit ?
w
08-10-19, 03:43 AM
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The threads will be stronger than original, but there'll be less crank metal holding onto it... Admittedly, that shouldn't be a problem for today's beefy cranks, but I wonder how some of the slimmest cranks would fare.
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Sheldon Brown's bike info ~~~ Park Tools repair help
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08-10-19, 04:06 AM
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Thanks so much for all the advice. I should have mentioned i'm based in the UK. I think the cheapest option is to swap out the whole crankset which I can replace for ~£30.00.
Is it possible to just replace the crank arms ? Are they all the same design i.e I can buy a 175mm generic arm and it will fit ?
w
Is it possible to just replace the crank arms ? Are they all the same design i.e I can buy a 175mm generic arm and it will fit ?
w
Hows this https://www.bike-discount.de/en/buy/...ry_country=190
08-10-19, 07:13 AM
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When replacing one arm, be sure the orientation of the square is the same. Some are available in a "diamond" configuration, 45 degrees shifted from a "square." As you can imagine, this is quite critical.
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08-10-19, 11:10 AM
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If that was in response to my post, look at this thread: https://www.bikeforums.net/bicycle-m...-parallel.html
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08-10-19, 12:29 PM
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If that was in response to my post, look at this thread: https://www.bikeforums.net/bicycle-m...-parallel.html
This one cracked me up.......
"I have a useful trick for mounting square cranks on my diamond spindle.
I clamp the bike in my workstand and use the workstand's rotating head to tip the bike forward 45 degrees."
08-10-19, 12:50 PM
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But the square is really a diamond 
I would never put a different arm on.... I would replace the whole chainset, so it would never occur to me that some are different.
But is a square turned 45 degrees really a diamond?
I would never put a different arm on.... I would replace the whole chainset, so it would never occur to me that some are different.
But is a square turned 45 degrees really a diamond?
