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new bike > little ache: too high, new pedals, crank length?(4 posts)

new bike > little ache: too high, new pedals, crank length?Gianicolo
Mar 14, 2003 2:11 PM

I just got my new bike today. Same size, same kind of carbon frame as my training bike.

After a first ride of about 2 hours I have so ache at the back of my knees, and back of my legs. What is the cause (?):
- new pedals (I now ride SPD-SL instead of SPD-R), my seat has to go down a bit because of that?
- new cranks length: my new bike has 175mm cranks, my old had 172.5mm. Does my saddle has to go down a bit then, or is this just a little ache to get accomodated with this?

Thanks in advance...
re: new bike > little ache: too high, new pedals, crank length?filtersweep
Mar 14, 2003 2:55 PM
Do the Ls really have a lower platform than the Rs? It looks like it would be the other way around.

I'm guessing you just need more time to dial in the ride. Even with "identical" bikes there are subtle differences, and a mm here and there can really add up.
re: new bike > little ache: too high, .....yes.davet
Mar 14, 2003 3:06 PM
Generally longer cranks mean a lower seat, if the shorter crank seat position was correct. Also if your pedals have a lower stack height, your seat should be lowered.

Overall, it sounds like your seat should be lowered about 3.5~5mm. It doesn't sound like much, but it can make a big difference.
re: new bike > little ache: too high, .....probably.Gianicolo
Mar 15, 2003 4:46 AM
Hey, many thanks for the answers,

According to Shimano the SL's are indeed a bit lower that the SPD-R's. Also the crank length may cause the problem, and indeed, 2 bikes can't be 100% the same.

On my ride today I stopped after half an hour, and changed the hight of the saddle by about 3 or 4 mm. Apperently it went better, but I still feel that little pain in the back of my knee (but most probably it's still the pain of yesterday I'm feeling). So it'll be better within some days.

Thanks very much for your advise!!