Hi,
Managed to find myself a nice second hand road bike but it has a standard chainset and wish to fit a compact (for Alpine duties...)
It's got a 105 chainset at the mo so can I just change the rings or am I better off changing the lot?
What the cheapest way of doing it as assume could sell the standard if replaced the lot.
The drivetrain looks pretty good so am assuming new rings would work fine with existing set up.
I may be wrong but I think the BCD is different on a compact. You will probably be able to pick up a compact chainset on the evil bay/forums for less than two chainrings.
Cool thanks - did wonder about the BCD...
You will struggle if at all getting smaller rings for a normal chainset-albeit you can do it the other way round.
cheaper just to buy a nearly new compact of e bay for £50
colwyn, ive got a brand new unused Sram GXP s350 chainset and bottom bracket I was going to advertise- 34.50and 175mm. RRP in total about £130, but asking £80 ish. email in profile if you are interested .
smallest ring a std Shimano double will take is 38
compact is 33
Look for Tiagra HT2, Truvativ Elita, Sram Apex etc. for budget chainsets. I run an Elita on the wife's hack and it's well finished and stiff.
SRAM apex from Ribble is good value, just bought one myself...
http://www.ribblecycles.co.uk/sp/road-track-bike/Chainsets-Road-Sram-Apex-Black-10-Spd-Chainset/SRAMCHAR290
OP are you just getting in to road cycling?
You may need a front mech too.
I thought about that - not looked at it properly but was hoping I could adjust the existing one but guess it's a new front mech if it's a braze on type one?
[i]compact is 33[/i]
Compact is 34.
No need for a new front mech, Shimano don't acually make a compact front mech. Just drop yours down slightly.
You can potentially fit a 33t ring to a compact if you can find one though, which I think was the point reggie was making.
But yes, standard ring sizes on a standard chainset is 53/39, compact is 34/50.
BCD on compact = 110 on standard = 130
Smallest chainring you can get on a 130 is 38. If you have a 27 cog on the rear, you are pretty close to a 34:25. But a new chainring and new cassette - cashwise you might as well go compact. It is just far better for your knees and sanity if you are going to be riding up proper mountains, we just dont have them in the UK, and nothing can prepare you for it.
Where are you going to be riding? How fit are you? How new to doing big alpine climbs are you?
Next time I go to the Alps or similar eg Ventoux with the road bike I will be taking a 34:27.
Done enough road riding in the Alps to know I need a compact...!
Looks like I'll just get the whole thing from the classifieds or cheap new, should be fine with existing chain etc... as drivetrain looks pretty new.
we just dont have them in the UK, and nothing can prepare you for it.
But we do have steeper climbs. Agree we don't have the 2 hour grinds, but plenty of steep stuff. Barhatch Lane out of Cranleigh for example, as your name alludes to.
IMO if you can ride that sort of stuff on a standard chainset you'll be alright in the Alps too. Not to say that I wouldn't have a compact next time I'm building a road bike.
33t ring for a 110mm BCD compact chainset
http://www.dotbike.com/ProductsP2466.aspx
http://www.spacycles.co.uk/products.php?plid=m2b0s149p433
If I'd have asked whether I needed a compact or not I'd have put that in the post...!
I worked out in Alps last summer, was mostly mountain biking and borrowing a road bike (that had a compact....)
Thanks for the wisdom though...
My comment wasn't aimed at anyone specifically (least of all you), was just responding to the "we don't have hills like that" comment. IMO if you're fine on a standard over here, you'll not suddenly struggle in the Alps, assuming similar distances, obviously if you do 20 mile rides here and do and do 200 miles in the Alps it's a bit different.
And as I said, I'd be very tempted by a compact next time - similar philosophy to the MTB, smaller rings so you can keep it in the big ring more.
If I'd have asked whether I needed a compact or not I'd have put that in the post...!
I can't believe that you were brave/foolish enough to ask about a compact using your standard login, nor that nobody has suggested yet that you MTFU. Which I'm now doing.
Thinking about it probably don't need any gears at all...!
Am planning to do the Marmotte if you're up for it - need to get out of a stag do that w/e first though...!
Njee
Do a 5x hill repeat on Barhatch Lane it is still not going to prepare you for Ventoux/Galibier/Tourmalet, you will be fit enough yes, but it us the unending horribleness that gets you.
21% on Barhatch means somewhere on this road is a 21% ramp.
8% on an alpine climb means 8% for... Ever.
Anyway OP knows he wants compact and rightly so IMO spinning it is just so much nicer than grinding it
My fave Alpine-feel climbs are the A4051 out of Treherbert and the A4107 past Afan Argoed, because they start in towns, climb up through the tree line and finish on barren passes. And they are long too even by UK standards, steady and relentless.
Oh and the Blorenge too, because it's consistently steep for quite a while and there's a very Alpine-esque hairpin in the middle. Did that with a standard chainset, that was f'in grim 🙂
(Yes I know they are a fraction of the length and altitude of the Alps etc etc but I am talking about approximations here)
Njee etc... – absolutely no offence taken at all from any of the posts - however I feel definitely "need" a girlie compact in the Alps...!
When legs are fresh it makes no odds what gears you have but when doing back to back climbs for hours on end it’s nice to have some easy spinning gears in the bag…
I find it similar to 12 hour races etc… where as it progresses you end up using lower gears on the same climbs as the laps pass by….