So this summer I’m planning to build up my first ‘proper’ bike. At the moment I’m on a Deore-level hardtail that I bought complete and while I love it to bits I’m now getting more into racing so would like something a bit more serious. With that in mind I am planning on a lightweight 100mm travel hardtail build primarily built with second hand stuff. I have a few random questions…

1. I’m planning on sticking to 3×9 as I can only afford to keep one bike and would like the granny for maraton-distance stuff and a big ring for the short road stretches. Will it still be easy to buy drivetrain components or are Shimano/Sram phasing these out in favour of 10 speed over the coming years?

2. Bottom bracket standards – does the BB have to be a specific size to fit the frame (e.g. like seatposts are) or do they all fit? Excluding of course press-fit standards like BB30, I’m just referring to ones that screw in.

3. Cranks – I take it these have to fit the BB so you can’t have Sram cranks on a Shimano BB and vice versa? Can you put XT cranks on an XTR BB?

4. Are drivetrain components interchangable from various brands? I know you can’t have a Sram rear mech with Shimano shifter and vice versa but other than that is it all good? Would Sram shifters and Sram rear mech, with Shimano front mech and cranks all work?

5. Brakes… how important are hose lengths? If I buy brakes with hoses too short will my LBS be able to put a new hose in or am I doomed?

6. Could someone please give a brief rundown of the post mount vs IS standard?

I think that’s it for now… Sorry for the barrage of questions but the numerous standards in the bike industry have left me confused to no end. Thanks in advance for any help 🙂

Google for your answers, you’ll get conflicting advice here. Or make friends with your LBS, and listen to their top mechanic.
enjoy building your bike, then enjoy riding it 🙂

Three/nine will be around for plenty of time yet.

If you buy a new cranks that is hollowtech 2 it will include the bb and required spacers. Go for Slx or better.

All 9 speed mech will work with any modern 9 speed cranks, IME stick with Slx mech and xt shifters.

Easy job to replace brake hoses. Avid elixirs or shimano Slx brakes are good vfm versus performance

1. Dunno, as i don’t know what the plans are of Sram/Shimano over the next few years.

2. BBs are either 68mm wide, or 72mm wide (Unless it’s a big DH bike which is 83mm) These share the same bottom bracket, just with extra spacers on 68mm BBs (For external BB)

3. You can put XT cranks on an XTR BB OK. I’ve ran raceface cranks on a shimano BB and a hope BB OK.

4. Yes, for the rear stay with the same brand (But make sure that you only run 9sp mech with 9sp shifter) For the front, i used to run (And still do) a sram shifter with a shimano front mech. For the front mech, you can chop and change.

5. You can put longer hoses on OK, but just remember, if the brakes are cheap, it’s sometimes more cost effective to get a new brake than replace the hose. If the brakes are new, the issue should be that the hoses are too long.

6. http://en.wikipedia.org/wiki/Bicycle_brake#Calliper_mounting_standards
OR

1 You can still get 7 & 8 speed kit so you’ll be fine. Just don’t expect a huge choice as time passes.

2 Yep, your bb width is determined by the frame/ shell . Manufacturer site will tell you what you need but many BBs accommodate both.

3 Correct, but it’s not that black and white as you can mix & match in many cases

4 Shifters, mechs and cassette from the same manufacturer to keep it simple.

5 Not for function, but they do flap about if too long! Most need cutting.

6 Post good, IS bad 🙂

If it’s your first build keep it simple.

68 or 73