Bicycle Mechanics - Replacing downtube shifter washers

Hey everyone, are the plastic curved washers that go between downtube shifters and the frame necessary? I can't find any replacement pieces, and I figure that frames have different downtube curvatures anyways. Can I just use an appropriately sized flat washer? Thanks.

Yes, they are essential. Nothing is added that is not needed. I am not sure exactly which washer you are talking about, but the old lever style shifters had tension washers. These are actually cup shape and they are specific to the shifter.

If you have old shifters, the general rule of thumb is that if the tension washers are shot, the levers are toast. I have never been able to find them for sale. Maybe someone on the forums knows where to get them - and if you do PLEASE post.

Tinkeric,

I assume you're talking about Shimano down-tube shifters, as those are the only ones I've seen that use bases that are curved to fit the down-tube. The parts you're referring to are called Lever Boss Covers and provide the limit stops for the levers. You can get the part numbers for them here:

http://bike.shimano.com/media/techdocs/content/cycle/EV/bikecomponents/SL/EV-SL-7800-2281A_v1_m56577569830609197.pdf

Installation instructions here:

http://bike.shimano.com/media/techdocs/content/cycle/SI/Dura-Ace/ShiftLever/6J50B-SL-7800_7700-EN_v1_m56577569830605247.pdf

You can buy'em here: http://www.loosescrews.com/Products/SH-6433810-1.html

Regards,
Bob P.

Tinkeric,

I assume you're talking about Shimano down-tube shifters, as those are the only ones I've seen that use bases that are curved to fit the down-tube. The parts you're referring to are called Lever Boss Covers and provide the limit stops for the levers. You can get the part numbers for them here:

http://bike.shimano.com/media/techdocs/content/cycle/EV/bikecomponents/SL/EV-SL-7800-2281A_v1_m56577569830609197.pdf

Installation instructions here:

http://bike.shimano.com/media/techdocs/content/cycle/SI/Dura-Ace/ShiftLever/6J50B-SL-7800_7700-EN_v1_m56577569830605247.pdf

You can buy'em here: http://www.loosescrews.com/Products/SH-6433810-1.html

Regards,
Bob P.

Wow, perfect response. I see Shimano calls the part an adapter/Lever Boss Cover. Is loosescrews one of the best small parts retailers? Thanks.

Shimano makes two style base plates for their downtube shifters. The curved ones were intended for "standard" diameter (1-1/8") steel tube downtubes and the flat back style is for "oversize" steel, Al, carbon and Ti tubing. The flat ones will work on standard diameter steel tubing but don't look as elegant.

Shimano makes two style base plates for their downtube shifters. The curved ones were intended for "standard" diameter (1-1/8") steel tube downtubes and the flat back style is for "oversize" steel, Al, carbon and Ti tubing. The flat ones will work on standard diameter steel tubing but don't look as elegant.

Thanks for the post. Believe it or not, I'm "downgrading" from STI shifters to downtube shifters on an aluminum frame, so I'll need the flat back plates. I only see the curved lever boss covers on loosescrews; do you know where I can order the flat ones?

Also, according to this thread (http://www.bikeforums.net/showthread.php?t=257614&highlight=mcmaster+washer) I can just buy an appropriate washer instead of the official Shimano part. Really?

Loose screws is good, as is bike parts etc.

You can grind the curve edges off of the curved base plates to make them match oversize tubing.

Chris Kelly used to modify Shimano curved base plates by grinding the backs perfectly flat to match the mounts on his "Take Offs" adapters.

Check out Loose Screws I think they have what you want look for Lever Boss Cover