Crankset advice please.

gazspaz
gazspaz Posts: 10
edited April 2016 in Workshop
Hi,
My bike (supersix Evo) currently runs Ultegra 6800 with an FSA SLK 50/34T BB30 172.5mm Crankset.

Im a bit of a short arse at 5'7 (bike size 52) so was wanting to try a 165mm crankset. Ive ordered a second hand FSA Gossamer from eBay to try for £35 :D . If the shorter crank is noticeably better for me i would like to upgrade it to something similar to my current SLK.

Sticking with BB30, Will an SRAM Crankset work with the rest of the Ultegra setup?

Searching for BB30 Cranksets with 165mm arms, SRAM seem to have the most choice and cheapest.

have any of you got any experience using a shorter Crankarm? Or am i waisting my time and Cash?

any advice appreciated. I'm not the most technical minded or a very experienced cyclist.. I normally Fell run but have a niggling knee injury so plan on biking mainly this year.

Ta

Gaz

Comments

  • lesfirth
    lesfirth Posts: 1,382
    I am about your size.I fitted 165 cranks to one of my bikes. I have 170 on two other bikes. Switching between bikes I am not aware of any difference. The load on my knees my be different and I may be able to pedal at a higher cadence but I have no facts to back that up.With no other factors to consider e.g. component weight,cost,bling,I would choose 165 but I would be happy to fit 170.
  • MikeBrew
    MikeBrew Posts: 814
    Surely if you have a cheap 165 crank set winging it's way to you, the best feedback you're going to get is from fitting it and riding the thing. Worry about SRAM compatibility etc, when you know if you're in the market for one. I.e. once you've decided whether 165 is for you.
  • StillGoing
    StillGoing Posts: 5,211
    gazspaz wrote:
    Hi,
    My bike (supersix Evo) currently runs Ultegra 6800 with an FSA SLK 50/34T BB30 172.5mm Crankset.

    Im a bit of a short ars* at 5'7 (bike size 52) so was wanting to try a 165mm crankset. Ive ordered a second hand FSA Gossamer from eBay to try for £35 :D . If the shorter crank is noticeably better for me i would like to upgrade it to something similar to my current SLK.

    Sticking with BB30, Will an SRAM Crankset work with the rest of the Ultegra setup?

    Searching for BB30 Cranksets with 165mm arms, SRAM seem to have the most choice and cheapest.

    have any of you got any experience using a shorter Crankarm? Or am i waisting my time and Cash?

    any advice appreciated. I'm not the most technical minded or a very experienced cyclist.. I normally Fell run but have a niggling knee injury so plan on biking mainly this year.

    Ta

    Gaz

    Similar height and I use 165mm on my No.1 bike. I use 172.5 on my second bike and find that doing high cadence drills on that help make keeping a high cadence (95-105rpm) on the shorter crank arms easier. If you want to spin a high cadence, 165mm will be easier, but if you like to grind gears at a low cadence, I wouldn't bother swapping. As long as you're knees aren't being stressed with 172.5mm of course.

    The SRAM crankset will work fine with Ultegra.
    I ride a bike. Doesn't make me green or a tree hugger. I drive a car too.
  • keezx
    keezx Posts: 1,322
    A common made mistake is keeping the saddle at the same heigth with different crank lengths.
    IF you change to 5 mm shorter cranks, RAISE the saddle 5 mm.
  • gazspaz
    gazspaz Posts: 10
    Thank you, I did look into the science of the shorter crank but would rather have your opinions who have experience with both. Ill give the 165 a go and lift the seat.

    I think the higher cadence will be better for me than grinding bigger gears. Ive had "runners knee" since a trail marathon at the start of feb. Its fine when I'm spinning away on the bike, but can feel it more pushing on the bigger gears, especially out of the saddle on climbs.

    Thanks again.
  • jgsi
    jgsi Posts: 5,062
    Its all pseudo science ... race bike 172.5... fixie/singlespeed for winter and commuting .. 160

    Can I 'feel' a difference,, can I feck.. as I say pseudo science by wannabe knowitalls... emanating by this modern annoying trend of being influenced by so called experts flogging you stuff.
    my advice if you got a bargain, call it a bargain.
  • keezx
    keezx Posts: 1,322
    It's certainly real science, it's all done a couple of years ago and the conclusion was: it doesn't matter.
    (Google report Jim Martin on crank length)
  • StillGoing
    StillGoing Posts: 5,211
    Just because one person isn't sensitive to the differences doesn't mean somebody that is is wrong. Plenty of riders advocate the use of shorter crank arms, but I suppose they're imagining it too. :roll:
    I ride a bike. Doesn't make me green or a tree hugger. I drive a car too.
  • pinno
    pinno Posts: 51,784
    Currently selling a Record 10 chainset on flea bay which were 'far too over sized, you'll do your knees in bollox bollox' at 177.5mm's. I'm only selling because I bought a compact. Never noticed the difference in any shape of form. I have ridden 175's for donkeys but I got that one cheap.

    Looking at the posts above, i'm not such a short 4rse after all :D
    seanoconn - gruagach craic!
  • svetty
    svetty Posts: 1,904
    @ OP

    The important measurement isn't your height but your inner leg length. Having said this I'm increasingly of the view that the range of crank lengths is such that relatively small differences in crank length make minimal difference in the real world as your neuromuscular system adapts to whatever length you are using. The placebo effect also comes into this......
    FFS! Harden up and grow a pair :D