Gear shifters when you convert a racing bike to a comfort bike
 

I was intending to convert a mid-1980's Miyata racing bike into a 'comfort' bike for upright riding, by putting a really long (280 mm) quill on it with new 'classic' handlebars with a 5" rise and of course will need to replace the brake levers. I'd be sitting pretty.

Now here's my question: The bike has downtube shifters, and I'll be waaayyy up there sitting upright miles from the shifters. As best as I can determine these are my options:

1. Shifters mounted on the top of the steerer tube where the quill exits, as on vintage Schwinn bikes. The problem with this solution is that it's still way down there. Now the question: Do they make quill-mounted paired shifters, similar to quill mounted front brake cable stop (see photo)?

2. Bar end shifters. The issue I see with this is that the cable would have to go underneath the foam grips and would exit right where the brake lever is located.

Comment?


https://cimg0.ibsrv.net/gimg/bikefor...dd32884397.jpg
Quill mounted brake cable stop. Do they sell double shifter levers that clamp on like this? I couldn't see anything like it.

Stem shifters clamp to the quill. SunTour Power shifters are my favorite for friction shifting. Indexing might be trickier.

quill mounted shifters are referred to as "stem shifters". you can mount them high up the quill as you like...though they're typically lower to the head set. and, yes...same type of clamp as your cable stop

have you considered thumb shifters? very popular, economical and easy to use

The third option is handlebar-mounted "thumb" shifters. These mount on the handlebar inboard of the grips.

I will bet that your bike doesn't have index shifting. You need "friction" shift levers, which is how all of us learned to shift in the old days. There are still some nice friction thumb shifters being made- search for SunRace SLM10.

Oh, heck- I already did the search: SunRace | SLM10

https://cimg5.ibsrv.net/gimg/bikefor...b5b8d5542d.jpg

Hey thanks gents!

This is just the information I was looking for.

And the options are economical too.

And yes, these would be friction shifters. (This bike is really vintage incl 27" wheels.)

One question about thumb shifters. They would be mounted medial to the brake levers. Wouldn't that interfere with the brake cables?

Thumbies sit at the top of the bar just after the brake lever, the brake lever should be down about 10 degrees from horizontal so well below the shifters with cables completely out of the way. The Sunrace are a fairly affordable set, Microshift has a nicer set but they're hard to screw up and the sunrace do a good job.

Bar end shifters are designed to fit into road drop bars, which have larger grip diameter than mtb/cruiser bars. So they might not work.
I think the MTB thumb shifters are your best bet.

I recently converted an old 12 spd Fuji to flat bars and thumb shifters. Here's what I did:
1. changed freewheel to 7 spd as good shifters for 6 spd are hard to find and it needed replacing anyway. 7 is the most gears you can safely use on a freewheel without bending axles or re-dishing wheels. I did not need to extend axle on drive side but this depends on your bike and some may need an additional spacer for the wider 7 spd to fit in the frame. Cost about $25
2. New 7spd chain KMC Z $9
2. Used a cheap clamp-on downtube cable stop to replace the 2 downtube shifters (if your bike had stem shifters then this is probably not needed). $10
3. Bought cheap 2x7 thumb shifters. Any brand will do like microshift or cheap Ebay off-branded ones perhaps. $20-$25. I had some Shimano Acera ones around.
4. re-cable with longer inner/outer cables.
5. It already had a Claris rear derailleur which is index compatible but any old 6-10 spd Shimano derailleur will work. The brake levers were also OK with the shifters.

And it rides great. Shifts are super silent and smooth. Freewheel with hyperglide ramps help here too.


https://cimg7.ibsrv.net/gimg/bikefor...819d1ca171.jpg
https://cimg2.ibsrv.net/gimg/bikefor...5db1fc842f.jpg
https://cimg3.ibsrv.net/gimg/bikefor...1e72093770.jpg
https://cimg5.ibsrv.net/gimg/bikefor...c26e6414fa.jpg

One thing I found about converting an old road to a flat bar comfort bike is the gearing. I ended up running a 42/30 (inner/middle) to a 7 speed 13-32 freewheel. The 42-13 is still an easy 20mph gear, but it rarely sees much use.

For me, it made sense to install a mtb rear derailleur for a larger cog and a bit more wrap. In doing so I use a combination of a thumb shifter for the front derailleur and a mtb trigger shifter for the rear derailleur. Makes it a pretty lazy day rider.

John

my vote for thumb shifters..... there are right where you need them and at least for me on a 1x8 setup work super well

Thanks again for all the great info and ideas! I'm excited about the conversion.

Thumb shifters seem to be the way to go. It will take getting used to with friction shifters but seems to be the most ergonomic solution

I'll also convert the schrader holes in the rims to presta using the Wheels Manufacturing grommets (see photo). I was going to cut them down so they're flush with the outside rim when in place. Using threaded presta valve stems with the nut in position will provide for a stable seat for the valve stem.

https://cimg2.ibsrv.net/gimg/bikefor...038ab9f7b5.jpg


I think these are the most logical solution from an an engineering standpoint of the several schrader to presta conversion options out there. But need to be cut down the the thickness of the rim so they're flush with the rim when in place, purely for cosmetic reasons.

Don't cut them down. They need to have a little height to stay in place if you lose pressure, the tube slips, and the valve tips over.

A friend had his Presta rims drilled for Schrader valves- his theory was that if he had to buy a spare tube at Wal-Mart (he rode a lot of self-supported tours), he could always use a Schraeder tube if that's all they had. I live dangerously- all my bikes have Presta valves and undrilled rims.

Thumb shifters are definitely the way to go on a vintage flatbar conversion. The Sunrace M10 are a nice choice; I’ve used them to replace the ‘Gripshift’ on my kids’ bikes, they just work really well, especially for how inexpensive they are.

Another good bang-for-the buck upgrade is a modern SIS (Shimano or sunrace) freewheel and a modern 8-speed chain. Even with friction shifters and a vintage RD, the shifting is way smoother than with vintage ‘flat-cut’ stuff

Your friend who drilled out his Presta vale holes to Schrader size has some insight, I have to admit.

If the Presta valve was threaded, and you had the nut cinched down to the level of the rim I can't see the valve stem going anywhere even with a flat.

better yet, cut them to be under the rim, and use a stepped presta nut (like come with Continental tubes) to keep the valve centered and you would never know there is a converter at all. Very clean. The primary reason for the grommet is to keep the tube from herniating at very high pressures.


https://cimg6.ibsrv.net/gimg/bikefor...3bef4c830.jpeg

[QUOTE=aggiegrads;22051395]better yet, cut them to be under the rim, and use a stepped presta nut (like come with Continental tubes) to keep the valve centered and you would never know there is a converter at all. Very clean. The primary reason for the grommet is to keep the tube from herniating at very high pressures.


https://cimg6.ibsrv.net/gimg/bikefor...3bef4c830.jpeg



I'm starting to think the best solution for the Schrader-to-Presta rim modification might be to simply put a flat washer on the inside of the rim under the rim strip, with a hole in the washer that's just large enough to pass the Presta stem (6 mm) and that covers the Schrader hole from the inside, and the stepped presta nut depicted in your photo screwed down from the outside. Those Presta nuts can be purchased inexpensively or the LBS might actually have some tubes with those nuts they're trashing I could get for free.

Suntour thumb shifters as used on 84 Stumpjumper, ratchet shifters, forgot name, XC2? no rubber , just nice Al, sweet lookin,

work forever with no maintienence

Another more gimmicky/novelty option would be stick shifters-which were popular on 70s era Stingray, Krate, Spyder type bikes in the early 70s. They usually mount on the top tube, some mounted on the head tube, some on the stem. Some existed in 1x5, 1x6, 2x5, 2x6, and 2x7 versions. Maybe the 2x7 were indexed but the other were friction style.

AFAIK stick shifters were banned.