weird hybrid build

lucasf09
lucasf09 Posts: 160
edited August 2011 in Workshop
Hi,
My mate (honest), suggested he wanted to build a hybrid, but not what one would normally consider a hybrid.
He has an old road frame, but bi group of wheels. He asked me if it would be possible to buy a cheap mountain bike and transfer the groupset, as be says this will be cheaper than buying a road groupset.
I said I would think about it, but basically, I think if the mountain bike is shimano equipped (which cheap ones generally are), the splines on the wheel should be compatible. Obviously the wheels wont be, but at least he would have a cassette. I believe mountain bikes also have wider bbs, but this might be solved by some spacers. But otherwise the mechanics should work.
I also told him that if the mb comes with sti shifters, he would have to use track bars rather than drops (or have the shifters and brakes in the tops, making it a suicidal bike on the drops) . Although one solution could be having non shifting brakes where they go normally, and down shifters for the gears.
What are people's thoughts? And sorry about the length of the post.

Comments

  • Monty Dog
    Monty Dog Posts: 20,614
    Check out the quality of cheap MTB bike components before making any decisions - there is often a reason for why they're cheap. I presume you mean flat bars not track bars? Track bars are generally very deep-drop bars. Until you get down to specific details of parts, almost impossible to answer general questions
    Make mine an Italian, with Campagnolo on the side..
  • maddog 2
    maddog 2 Posts: 8,114
    if you run a flat bar then it's possible. If he wants drops then it's not really practical.

    Issues:

    - you'd have a mtb drivetrain on a road bike so gearing would be low
    - the road bike needs raod brakes, so your mtb levers (assuming they are V -brake) would need changing
    - you'd need to check the front mech band diameter, seatpost diameter, seatpost clamp diameter, stem type and diameter, BB width etc. to ensure the swap was practical.

    might be better off fitting road parts...... :wink:
    Facts are meaningless, you can use facts to prove anything that's remotely true! - Homer
  • mz__jo
    mz__jo Posts: 398
    The cassette will swop if the road wheels are Shimano or compatible (SRAM should go)
    The bottom bracket should fit into the frame without any problems (a lot of mtb brackets are 68mm just like road).
    The rear derailleur should work without too many problems on 7 and 8sp (I have mixed mtb derailleur and road levers, and inversely, also Sachs levers with Shimano mechs and inversely) but 9 and 10sp may be different.
    The front mech may well pose problems, firstly because you have to make sure that it is bottom-pull, which quite a lot of mtb ones aren't, (although they are sometimes dual-pull to work in top and bottom pull). The front mech may also be too bulky to fit on your road frame between the wheel and the seat tube (this is a very probable problem)
    The hubs will definitely be uncompatible with your frame as they will be 135mm oln and road frames are 130mm (unless it is a cross frame or one of the touring frames designed for mtb hubs).
    The brakes won't fit.
    The brake levers will be for V-brakes and will give a very short travel with road brakes. You may like this or not, but it is not usually recommended.
    The stem on your road bike will have to be for 1" diameter bars to take mtb bars to mount mtb levers for the mechs.
    The cranks will be 175mm and might just give an overlap problem if you are not careful.
    Do you really want to buy a whole mtb just to recover a rear mech and a bottom bracket that may or may not be the right length?