Bicycle Mechanics - Swtich from STI to down tube shifter

For the front crank only. Has anyone done this? Can't be that hard for a double can it? I want to switch my 105 front from STI to downtube.. Any tips?

what is the reasoning?

Method of mounting of the lever is main problem. You may be able to use a
standard downtube shifter mount, if it can be found and your tubing is close to
a standard size. 8spd STI shifters mounted on bosses on the down tube that
were threaded and a down tube lever could be modified to mount to this, maybe. It would have to be examined and different levers use different mounts but all had a center bore and a screw threaded attachment. More recent bikes have used only cable stops and not the full adjusters of the 8spd era, and a lot of the cable stops are near the head tube and useless for mounting. If the frame is Al or steel it is probably substantial enough to use a threaded mount (can't recall the trade name but frame builders and shop types can perhaps help)
that mounts irreversibly in a hole drilled in the frame. These are used for
permanent water bottle mounts routinely by frame builders. Absent specifics of the frame, a discussion with personnel at an elderly bike shop that hasn't been
cleaned up in 20yrs may produce some odd bits of metal that will suffice, left
over from bygone years. All kinds of transitional adapters and attachments
have been made over the past 30 yrs or so. Steve

Wasn't there a discussion a short bit ago about Lance doing this during parts of the TDF? Since then you have friction for the front chainrings.

As long as you have shifter mounts you should be OK, the only quality downtube shifters are DuraAce and you might have to get a pair. There are some cheapies out there that will work fine and only get you in for $15-20. They are, I think, seven speed shimano knock offs, Quality carries them, so your local shop should be able to get them. You may also find an acceptable used lever just about anything will work, Shimano, Campy, Suntour

what is the reasoning?

Lance Armstrong does it.

Lance Armstrong does it.

And if Lance Armstrong jumped off a bridge..............??

....its certainly not about the bike.

But, the STI shifters are a pain when it comes to making fine adjustments to the front mech (mine only has a couple of minor click stops in addition to the major shift between rings). A down-tube lever will let you set the mech perfectly to prevent chain rub in any gear.

My non-STI bike was upgraded last year with a set of Sora down-tube levers (cos about £30 for the pair). These are a very good quality item and have worked beautifully from day 1.

Cheers,

Ed

I have thought about doing this, too, NOT because LA does it, though I will admit that I hadn't thought of that as a solution until I read he did it. Then I was hesitant to do it BECAUSE he does. I may do it because, though my rear shifter and der always work well and stay in adjustment it seems like the front will want to act up just when I need it. I figure friction will eminate that altogether, and since it's not used frequently downtube won't be that inconvenient.

i see now, that makes sense.

Lance Armstrong does it.

No. Not particularly. But thanks.

And if Lance Armstrong jumped off a bridge..............??
Then Darwanism would make available some nice trek bikes, eh?

So, in anyone's opinion, can you simply cut the cable short, and place the shift into the cablle guides (it'd be on a cannondale frame)?

That's pretty much it if you have downtube shifter bosses. There won't be a barrel adjuster so you'd have to take up as much of the cable slack as possible.

I thought that lance did it becuase it was lighter then the two STI combo. if you notice, he only does it on his climbing bike.

on another note, I've never had trouble with my front STI, Im not sure what you guys are doing wrong. I don't find it particularly difficult to adjust.

I thought that lance did it becuase it was lighter then the two STI combo. if you notice, he only does it on his climbing bike.

on another note, I've never had trouble with my front STI, Im not sure what you guys are doing wrong. I don't find it particularly difficult to adjust.

I don't have particular problems with it. However, I find myself playing with the gears a little bit too much. I want to "force" my self to stick with a particular ring.

You could use the limit screw to lock out the gear you are trying to stay out of. Focus power, concentrate.

Yes, for heaven's sake man stay in the big ring :)

Front mech indexing is a fundamental engineering blunder, because it does not allow the rider to prevent chain rub in various gear combinations by fine-tuning the cage position. Ergo greatly outshines STI here, precisely because it does give the rider smooth control over the cage position. A friction downtube lever will provide even more precise control, because of the absence of (compressible) cable housing.

I agree with the other posters that the only challenge will be to mount the gear lever onto the downtube. Everything else will be very easy.

The secondary benefit of replacing STI is that your enhanced control, if properly deployed, will enable you to prevent overshifting.

I repectfully disagree, johnE.

Item #1. I think sti helps to prevent overshifting becuase there is definite click when you shift, but with friction, there is no positive indicator when you are in gear. Hearing a chain grind between the two chainrings is the worst sound in the world. Trust me, I run a friction bike and an STI bike, and I like the STI a lot more...

Item 2: When the cage starts rubbing, it means one of two things: you did not adjust your front mech correctly, or you should switch out of the ring you are in, becuase you are getting crazy crossed up. (big-big, small-small, you know)

If I may return to serious contributions...

I have bikes with STI and down-tube shifters, both setups are Shimano Sora. From experience the friction shifter gives more positive shifting between chainrings. It never over or undershifts, which is good considering that the chain rings are not supposedly compatible.

The STI lever needs to be pushed a long way before it begins to pull the cable for the shift from small to large rings, so it is more of an effort to make the change in the first place. This is not cable slack, this is the design of the mechanism. More-over, set up of the front mech to get the cage positioning correct to prevent chain rub has proved very difficult. The fine adjustment STI points give only *just* enough range to cover the shift in chain line from the 3rd to 8th rear sprockets (8 speed bike) - a reasonable range to demand in normal use.
I'm willing to accept that in this case more expensive components may perform differently, but the bike is not worth the expense that would be required and this is not such a serious problem that it upsets my riding.

Interesting debate,

Ed

My aged bike has SIS d/tube shifters working crappy old Exage changers front & rear. they work well , the front works great on SIS but the adjustment is quite criticle ( distance above the chainwheels & lateral angle to the chainwheels as well as the usual H&L adjustment) & the chainwheels must be true. I use'd to have biopace c/rings & then it was easyer to turn the centre selector to friction ,SIS was possible with the biopace but when the adjustment started to wonder the chain would fall off the big ring onto the crank occasionaly when up gearing .Glad the b/pace is gone but now they're on my rain-bike :( but thats even older, Shimano 600 friction shifters/changers. Getting the b/pace to work satisfactory on there was quite a mission in adjustment :eek:

And it worked just fine. Actually, I'm MUCH happier with the downtube shifters. My mechanic gave me a set of shifters, and I just had to take it apart, clamp it on, re-adjust the railleurs and cut the cables- VERY simple. The only trouble I had was if I placed the clamp right against the cable stop, there was too much friction so I moved it like half an inch forward and its fine.

Good luck!