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Frame Geometry Headbuster

ricktabor1ricktabor1 Posts: 272
edited April 2010 in Workshop
Hi everyone,
My friend recently asked me if I could turn his hybrid into a road bike. His bike is a Carrera Subway hybrid which he recently bought but has got into cycling so much, he immediately decided he wanted a road machine.

I worked out that if I bought drop bars, added sora 8 speed sti's and swapped the rear from SRAM X-5 to Deore, I could do it (with the help of CRC) for around £120.

Anyway, the point is that it then occured to me that the frame is a 20 inch which in road terms would be 50cm. Andy is a big bloke (requiring a 20" MTB/hybrid frame) and obviously a 50cm frame would be far too small. However I assume that the 20" frame would be longer than a 50cm road frame.

I can't get my head around whether or not the bike would be too small when given drop handlebars, or if it is all relative and it would just act like a sloped tube winter training/audax type bike.

I know this post makes for hard reading but if anyone can offer any advice, i.e. is it worthwhile doing or not, I would be very grateful.
Got to get up to get down


  • 2alexcoo2alexcoo Posts: 251
    MTB and road sizing are not really comparable. I'm 6'3" and ride a 19" (48cm) MTB, but the top tube is 600mm, which is longer than my XL (59cm) road bike.

    If the bike fits ok now you may find you need a shorter stem to compensate for the longer reach of the drop bars. You may need one anyway if the Subway has an MTB stem with a 25.4mm clamp (road bars are either 26.0mm or 31.8mm diameter).

    You'll also need to buy adapters to make the Sora levers pull the right amount of cable for V-brakes, as they are not compatible out of the box. The road shifters and MTB front mech may not play nice either, but I don't speak from experience on this point.

    If I remember rightly the Subway comes with chunky 26" wheels, so proper road tyres are out. A pair of decent 26x1.25" slicks is your best bet, so that's more money again.

    I bet the whole lot would end up costing £200... personally, I would sell it and buy a secondhand road bike for £300. Probably not much difference in cost overall.
  • ricktabor1ricktabor1 Posts: 272
    Cheers Zalex,
    Totally forgot about the v-brakes not being compatable with the road brakes. These kind of posts often prove so useful!!!

    I think you're right - for the money he my as well sell the bike and buy a decrnt road bike.

    Got to get up to get down
  • keef66keef66 Posts: 13,123
    I pondered this very thing a few years ago, quality rigid mtb, riding more and more on road. I put slick tyres on it which made a big difference, but anything else would've been financial madness.

    Stem, bars, sti levers (v-brake compatibility??) cassette, possibly chainset (chainring / chainstay clearance??) front and rear mech......

    So I've spent £400 and got a 30lb frankenbike

    So instead I spent £1100 on a road bike and gave the slicked up mtb to son for university
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