BrokenSproket

It was suggested in the Bicycle Mechanics forum to post this in touring forum also.


I am converting 1989 or 90 Specialized RockCombo with Shimano 7 sp cassette to touring bike, keeping the 7 sp cassette. Dropouts are 130 mm. I am not interested in friction downtube or bar end shifters although I understand why some tourers prefer them over brifters.

I have bought Shimano ST-2303 triple 8sp brifters, KMZ Z5 chain (116 links, 1/2"x3/32"), Alivio rear derailleur, and have either of two front derailleurs that I can use--Shimano Alivio or Shimano Tiagra triple.

The front crankset now on the bike is a wonderful classic Specialized 110bcd square taper triple crank which I must unfortunately replace because there is not enough room to shift from middle chainring to outer without front derailleur hitting the right spinning arm. Also, I don't believe it would index properly with the brifter.

I would like to keep the smooth spinning square taper bottom bracket if possible.

Questions:
The front crank is the only component I have not bought yet. I have found 8 speed triple crankset with square taper--Shimano Alivio. Will this index properly in the front with the brifter and chain I have? Also, which front derailleur will work best indexing with this setup? Rings will be either 22-32-42, or 28-38-48 with the small ring changed to 24t. Will I need to change the spindle length of the bottom bracket?

I am not against having a better crankset and changing the bottom bracket. Will a non-8sp crankset work with the brifters and front derailleurs I have? If so, what would you recommend? I realize I would probably need a norrower chain.

Are there other considerations I have not addressed to make this a properly shifting tourer with brifters?

Thanks in advance for your advice.

staehpj1

I have found that the 7, 8, and 9 crank sets all worked fine for me with 7 and 9 speed STI brifters. I bet a 10 speed would be fine as well. The front indexing just isn't that fussy.

BrokenSproket

Thanks for your reply.

fietsbob

It will be costly, need lever and rear mech and cassette to all be 'on the same page'

and road brifters offer no fall back if you or your bike fall and mess them up, ..

As someone who toured for decades with simple bar end shifters ,
I don't grasp why you reject the idea out of hand, but .

Given many of the coast riders are happy with them,
A ll you need is the money for the parts,
the bike shop to straighten out a potential bent dropout hanger [all to common].

[they will, also, be advantaged by Seeing the project you have in mind]

cables, housing, and the other various parts ..

Ahead of you, is a frame up rebuild , I suppose..
strip it and put some paint on, while you are at it,

at least thereafter, the condition of everything will be Known,
before starting out on your trip..

Shimano's K, 7 speed cassette for touring

imi

Hope I'm not missing something here, but why not get an 8-speed cassette?
Alivio costs $20

fietsbob

Ratios matter more than 'speeds', which is just a count of cogs and chainrings, after all.
Now if the frame is spread, another 5mm common Mountain bike wheels can be bought,
then the 9th cog and the rest of the kit can be purchased..
Advantage : screw up a wheel, and a bike shop will sell you a new one,
7 speed was so pre I-phone.

Thulsadoom

How is it you have a triple crankset that won't work with a triple front derailleur? How did it ever work? Sounds like you just need to adjust the derailleur.

You already have a 3/32 chain, why would you need a narrower one?

I'd use the Tiagra front derailleur.

Sounds to me like all you have to do is put it together and ride it.

rothenfield1

I kinda agree with this statement, if I’m reading the PM’s post properly. The indexing on the 8spd STI shifters should be the same spacing whether it is 7 or 8sp. Your 8th click just won’t do anything. It seems that your front D needs adjusting if it’s pushing out past your third ring. Sometimes a front D just doesn’t have enough swing to cover the range of a triple ring crank. I’m not sure about your Alivio, but the Tiagra is known for having adequate reach. You just need to play around with the limit screws.

BrokenSproket

fietsbob, Thulsadoom, and rothenfield1: Thanks for your replies but I believe you misread my post or I wasn't that clear. Not concerned about rear shifting or indexing of rear cogs. What concerns me is proper indexing of front crankset with the 8 sp brifters I have. Wanted to know which combination of derailleur and crankset will work for front indexing.

Thulsadoom

Here's where you confused me:

The front crankset now on the bike is a wonderful classic Specialized 110bcd square taper triple crank which I must unfortunately replace because there is not enough room to shift from middle chainring to outer without front derailleur hitting the right spinning arm.

If the front derailleur is moving out far enough to hit the crank arm then your derailleur simply needs to be adjusted. Then you can just use the crankset you have.

The indexing of almost any front triple brifter/derailleur/crankset combination will probably work fine. There's only three positions and most triple cranks have close to the same distance between the rings. Just suggesting you try it before you purchase more stuff.

staehpj1

I missed the "not enough room to shift from middle chainring to outer without front derailleur hitting the right spinning arm" part. That sounds like a derailleur adjustment should make it work with that crankset. Remember that in addition to the cable adjustment and the limit screws, the possible derailleur adjustments include moving it up and down the seat tube as well as changing the angle of the cage by rotating the FD on the seat tube.