ruirui

ok.., i'm currently in the process of gathering parts to make this transformation. my plan is to change my sirrus to a time trial setup and upgrade the largest chainring from 48T to a 52T.

here is what I have thus far:
- Syntace C2 Aero Bar
- Nashbar TT Bullhorn Bar
- Cane Creek TT brake lever
- Shimano 8/9 Speed Bar End Shifters
- Profile Cork Tape
- FSA 8/9 speed 52T 110mm Chainring

now i'm not sure i can use my existing brake/ deraileurs cables, so here is my current spec of the sirrus. it's the entry level sirrus.

FRONT BRAKE: Forged 6061 alloy, 85mm linear pull, multi condition pad
REAR BRAKE: Forged 6061 alloy, 85mm linear pull, multi condition pad
BRAKE LEVERS: Shimano EF-35, EZ Fire, integrated with shift lever
FRONT DERAILLEUR: Shimano T-301, 31.8 clamp, bottom pull
REAR DERAILLEUR: Shimano Sora
SHIFT LEVERS: Shimano EF-35, EZ Fire
CASSETTE: Shimano HG-50, 8-speed, 12x25t
CHAIN: Shimano HG-53
CRANKSET: Specialized five arm, polished arms
CHAINRINGS: 48Sx38Sx28S, Super Shifter
BOTTOM BRACKET: TH Sport, square taper, 68mm shell, 113mm spindle, sealed cartridge

so, is there anything else i may be missing or may need? please advise if there are certain parts i can reuse from the original setup. also, how hard is it to tune the shifters so they will shift correctly? any pointers? i would love to learn how to do this myself, so if someone can shed some light, that would be wonderful!

rui

supcom

Have you verified that your front derailer will handle the new chainring size as well as the difference between the largest and smallest? Also, have you verifed that your rear derailer will handle the total cable wrap caused by the new chainring?

ruirui

yup... khuon has verified that for me. so with my current 8 speed sora setup, it will be able to handle the new chainring.

Retro Grouch 

I doubt that Cane Creek brake lever will have anough cable pull to handle your oinear pull brakes.

ruirui

humm... i would think it should ok.. but then again this is my first time. i'll try it out first with the original brake line and see.

slide13

I'm thinking you'll also need a new stem. The bullhorn bar will have a road bar clamp diameter of 26.0. You current stem will have a clamp diameter of 25.4, which is what is used for flat or riser bars.

I also agree that those brake levers and brakes probably will not work well together. You may get it functional (or not) but I'm guess it will not work great. You could use a travel adjuster on the brakes if you have too, this is often done on tandems that use linear pull brakes with STI levers.

ruirui

humm.. good call on the stem part. i used my dial caliper to measure it and it was showing 26mm... so we'll have to wait and see. as for the travel adjuster.. what is that? never heard of it. i'll be doing this upgrade myself.. so we'll have to wait and see. i am sure there are some parts i am missing or will need.. so i'll keep you guys posted...

bg4533

Do you still have the stock suspension seat post? That will probably look pretty weird as well as feel weird in an aero position.

roadfix

If you, in the past on occassion have swapped cables, adjusted, replaced, installed shifters, derailleurs, headsets, B/B or done any other basic work yourself, this transformation should be a breeze.
As far as brake and shifter cable lengths......it's always a good idea to just have a complete set ready on hand if your old set is too short. Don't forget housing ferruls and cable ends.

ruirui

fixer.. actually i've never really swapped cables or done anything major like that before. so that's why i am a bit nervous.. yet looking forward to doing this myself with all of your help online. the good thing is there is a LBS near my house. but i am not so sure about me bringing a bike from a different shop into there. the LBS i bought this bike from is really far from where i live now. so hopefully they wont' diss me and not help me. hehe

demoncyclist

Cash is cash. I don't think a shop will dis you if you are going to pay them for their service. As for the brake cables, you will need something called a travel agent. It is a small eccentric pulley that converts the short pull from a road brake lever into the larger pull needed to move a linear brake properly.

ruirui

how much do those normally run? if they are too expensive.. then perhaps i'll upgrade my brakes too.. too many excuses i can use... hahaha

chuckfox

I did a similar brake change when I converted my flat barred Giant Excursion to a bull bar. You could do one of two things. You could go to older style cantilever brakes which will work with the road levers, or I switched to Tekro Mini-V brakes. They have a shorter arm than a standard sized linear pull brake so require less cable pull.

Road levers only pull about 11mm of cable where moutain style levers pull around 25mm. The linear pull brakes require the larger cable movement to function properly. The Mini-Vs fall somewhere in the middle. I've been able to get them to work nicely with standard road levers.

ruirui

humm.. i'm going to try it first to see if i can still use my existing cables.. then after that.. if the pull is too weak.. then i'll look into either getting new brakes or just getting the travel thingy...