chosing roadie crank length and 105 groupsets

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chosing roadie crank length and 105 groupsets

12 posts & 9 voices | Started 1 year ago by pinches | Latest reply from pinches

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pinches - Member

I'm building myself a roadie as a training bike for fitness mainly.

I've been handed down a litespeed frame from a friend, with a post and some bits, but i need to buy a chainset and some other bits like STIs.

I've always run 175mm arms on my MTBs, but the roadie ones seem commonly to be 170 or 172.5, and i'm not sure what to get, I'm 5ft 11 with a 32" inside leg if that helps?

Also, i'm shopping around for prices for some STIs and chainsets, 5700 105 seems to be cheaper than 5600, 5700 being the replacement for 5600 right?

thanks!

Posted 1 year ago #
ctznsmith - Member

Zinn says:

I have done numerous crank length tests for VeloNews and the results show that (1)there is no one crank length that works for a given body size and (2) standard stock crank lengths are arbritrary. It's worth experimenting to see what you like.

Personally as you're only 5ft 11 I reckon 172.5mm would see you right, but you do have quite a long inside leg for your height (I think), if you intend to do a lot of hill climbs then maybe track down a 175mm crank length they do exist for 105 (I have one on my road single speed).

5700 is the newer version of 105 which looks (and I guess has some of the design elements) a bit like Ultegra/Dura-ace...not sure why it would be cheaper than 5600 unless they've lowered the price as well.

Posted 1 year ago #
RealMan - Member

IME, the higher your average cadence, the shorter the cranks to go for. I spin a lot, so I always go for 170mm.

Posted 1 year ago #
romster - Member

Get yourself a compact 172.5 to get you up them big hills and maybe a nice 12/25 cassette. I've got some brand new 105 5700 shifters and a RD if you're interested? Well . . . . . I say "I", what I actually mean is JEJames have got em! In fact they we're ordered in to go on my bike but I ended up sticking some nos 08 Ultegra SL sti's on. Not sure if we've got the chainsets yet but sure i could sort you out fella. Let me know if you're interested, be more than happy to help you out where I can!

Posted 1 year ago #
kilo - Member

105 STI shifters have had a history off breakages / faults, which seems to be unique to that model, it may be worth seeing how much Ultegras would cost

Posted 1 year ago #
mugsys_m8 - Member

I have just had to buy a ultegra rear mechanical. The newer version was 20 quid cheaper than the older. Bit fitted as it does not match well with the rest of my older ultegra groupset.

Posted 1 year ago #
pinches - Member

planet X have got last years ultegra STIs for £150.

I think i'll go for a compact 172.5 with a 12-25 cassette.

I want to get black 105, i can pick up the rest of the groupset from work, just need a chainset and STIs as we haven't got them in stock, so romster drop me a mail (in profile) if you can help!

Posted 1 year ago #
romster - Member

stforum@jejamescycles.com drop us a quick mail and i'll be in touch tomorrow.

Posted 1 year ago #
redted - Member

5700 is cheaper than 5600 because they wanted to bring it more in line with Sram Force pricing. I've been riding production sample 5700 for 4 months and it is great, a marked improvement over 5600 wich wasn't shabby anyway.

Posted 1 year ago #
alexxx - Member

chris, I've got ultegra 5600 running compact at the mo and its ace for around the lakes and silky smooth everytime i get on it with no maintenance all you need to care about is how many people you can scalp! hehe.

I've got 170's and as you maybe remember im 5ft11 also with a fairly long leg

happy lycra wearing

Posted 1 year ago #
Mister P - Member

It was the early 5600 levers that had an issue but they were replaced with double / triple specific internals and that issue was solved. 5700 levers have had no known faults.

Posted 1 year ago #
pinches - Member

theres a fantastic 5600 groupset deal on merlin, but to get a comapact i have to get 175mm crank arms

Posted 1 year ago #

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