STEEL BIKE - Downtube shifters and bike upgrade options

svouts

Hi,
I have a late 70s Koga Miyata bike with Shimano 600 6x2 speed gears in very good condition. I want to upgrade the wheels and the transmission and use it as winter training bike.

I am going to cold-set the rear dropouts to 130mm to accommodate modern wheels. I will also change the derailleurs to Shimano 105. But I keep the downtube shifters.

Then, I have two options:
9-speed cassette with Shimano Dura ace indexed downtube shifters
8-speed cassette with Shimano SL-R400 (Sora) indexed downtube shifters

The 8 speed setup is cheaper to buy and replace and should be more durable in the dark wet rides (i.e. thicker chain and cogs last longer).

Any ideas on what are the advantages of Dura ace indexed downtube shifters over Shimano SL-R400 (Sora) ?

Ben6899

They're lighter and - subjectively - look nicer.

svouts

Thanks

So, 9 speed would be an advantage only if Dura ace downtube shifters are working much better.

Has anyone tried either Dura ace or SL-R400 (Sora) indexed downtube shifters?

david37

Check the D/A compatibility with the derailleur you are using. I seem to remember their being a pull ratio consideration for pre 97 DA.

Benefit of DA - looks nicer, a fraction lighter.

Sora is functional less pimp and cheaper, 6,7,8 speed chains are less than a tenner and cassettes cheap as chips. you can also get a cheap megarange derraileu and cassette, for a get home with weary legs option.

You can chuck it all away and replace cables chain and cassette every year for less than £30.

veronese68

My son has the DA 9 speed shifters on an old steel frame with whatever mech I had kicking around (definitely not DA) and it works fine so I don't think it's an issue. They work beautifully, just a shame the clearance on that frame means it won't shift to the 12 cog, although an 11 might work. The seat stay fouls the chain as it drops down.

davidof

Why don't you just ride it with the original wheels and transmission?

jbp

I went from 6 x 2 Shimano 600 Deraillers with Campag non-indexed down-tube shifters to 10 x 2 with no issues. I changed the chainrings and used RS10 shimano wheels cassette & chain off my summer bike. Suprisingly the existing shifters and the 600 deraillers work just fine despite going from an old school 6 speed corncob freewheel to 11-28 105 cassette.

svouts

davidof said:

Why don't you just ride it with the original wheels and transmission?

The original wheels are form 1977, they look good but the rim's braking surface is almost at the end of their life and they have a freewheel not cassette. I wanted 130mm with modern cassette so it is easy to get parts and cheap also, hence 8-9 speed cassette.

Then with modern wheels/cassette I would prefer an upgrade in the rest of the transmission so I can use the bike intensively for winter training, hence 105 derailers and 8-9 speed downtube shifters.

I would keep and restore the original parts so I can bring the bike in it's original stage in the future, when I would use it just for recreational rides, not for winter training.

svouts

jbp said:

I went from 6 x 2 Shimano 600 Deraillers with Campag non-indexed down-tube shifters to 10 x 2 with no issues. I changed the chainrings and used RS10 shimano wheels cassette & chain off my summer bike. Suprisingly the existing shifters and the 600 deraillers work just fine despite going from an old school 6 speed corncob freewheel to 11-28 105 cassette.

i just ordered a new pair of silver polished pair of handmade wheels! i wanted to use indexed downtube shifters so I can be faster and a bit more careless when changing gears. I could always go back to friction if indexed does not work.

svouts

Changing gears under pressure,
do you think the Dura ace 9 speed downtube shifters will work better than the SL-R400 8 speed shifters.

In other words, is it the shifters or the derailleurs and the cassette that would make a difference in smooth change of gears under pressure?

If the Dura ace shifters would not make shifting smoother then I would be fine with the SL-R400 8 speed shifters and the related 8 speed parts (chain, chainrings, cassette - cheaper option and more durable).

veronese68

It will be the derailleurs, cables, chain and cassette that affect that, not so much the shifters.