swap ultegra FC-R700 compact for Bontrager Race Triple help!

speckybecky

I'm wondering if anybody can help me. I've got two bikes and want to swap the chainsets over. Currently I have a giant TCR CW 2007 with a Shimano R700 Hollowtech II 34/50 compact chainset and a lemond with a Bontrager Race triple chainset. I have contacted giant and they have told me that the giant frame and shifters will work with a triple. Does anybody know whether it is a case of just removing the chainset from one bike and putting it in the other and swapping the chain and front mech over or is there anything else I will need to do/buy/look out for! Do I need a shimano triple chainset or will the Bontrager work?

Thanks for your help!

itisaboutthebike

Hi
before you start doing all this perhaps it mite be worth working out the gear sizes on each repective rig, as in reality you mite not actually gain very much by swapping the triple over.

Have a look at Sheldon Browns gear calculator - that will tell what you've got on each bike and then make a decision. 34x27 is not much different to 28x24.

If you do decide it's worth it, you may need to swap the rear mechs over as well. You don't say what rear mech you have with the R700 - if it's a double its unlikely to be able to cope with a triple (what are the chainwheel sizes ? 28/38/48 ? 30/40/50 ?).

Monty Dog

Swapping chainsets and bottom brackets will be OK - you might need to swap the front mechs too. Dependng on how worn the respective chains and cassettes are, you might find it easier to keep the existing chain on each bike - lengthening or shortening them as chain wear is more closely matched to the cassette than the chainset.

speckybecky

I didn't realise that the rear mech's were double/triple specific too but swapping them over shouldn't be a problem. The lemond has a 105 rear mech and the giant has an ultegra. The triple is a 52, 39, 30, the compact is a standard 50,34. I like the granny ring and the smaller jump between a 52-39 and a 50-34. If it isn't possible to swap I'm sure I'll get used to the 50,34 and just have to get fitter to get up those welsh hills!

Thanks again

Becky

itisaboutthebike

Hi again !
a lot of lasses(I'm assuming you are a lass !) actually change the 50 for a 48 and run 34/48 - this probably a betterfemale compact set up for most women (elite riders excepted !). This would give you a smaller jump from the 34.

Spa cycles do 48 Stronglight compact rings which will fit your R700 - go for the 7075 T6 ones - about £25.

I actually use a 34x48 compact myself(and I'm a bloke !) and find 48x12 plenty big enough these daze (well I am getting near to 50 !) - I probably wouldn't do if I still raced tho.

Shimano don't do a compact 34/48 chainwheel option (as yet - maybe next year ?)

You don't say what rear sprockets you've got on each - but 30x25 isn't really that much different to 34x27.

speckybecky

The bits I am swapping are both off of new bikes so wear and tear isn't an issue. I'm going to sell the lemond but wanted to swap the chainsets over before I do so because I really do want a triple and may as well change it before I sell the other bike. I've just heard back from lemond who reckon that I will need a new left shifter, I'm a bit confused because according to their website the shift/brake levers are Shimano 105 STI, w/Bontrager FIT reach adjust, which I thought were double and triple compatible. Anybody know otherwise? If it makes life any easier these are the two bikes I currently own!

http://www.lemondbikes.com/bike_archive ... womens.php

http://www.rutlandcycling.com/ProductDe ... goryID/277

itisaboutthebike

Hi again
personally I'd stick with the compact , and change the 50 ring for a 48 and buy a 12-27 cassette (about £25).

The R700 is a much better chainset than the one on the lemond (unless its also an outboard bottom bracket like the R700 chainset).

Your lowest ratio will still be the same 34x27 is the same as 30x25.

speckybecky

Thanks for your help. I decided to take it to my LBS who have done a fab job and I now have them swapped. I know the compact was a much better chainset (and more fashionable) and the actual gearing isn't that much different between a 34-27 and 30-25 but I like close ratios you get on a triple! I'm just not used to compacts and wanted lower gears than I was getting on my old bike with a 53/39 double. Anyway I guess I'll run the bontrager triple into the ground and then get it replaced with something shinier when I can afford it! At least it is all set up for that now.

I've got the lemond for sale (see road ads on this website), with the lovely ultegra compact chainset on it. The bike looks great, just wish I was a bit taller!