Advice on my low gears for my Retro 531 build.

[Spokesmann]

I run a 14-34 rear with a 48/38/28 Stronglight triple on one of my builds - it can tackle any hill.

What rear mech do you use, are you running a cassette for freewheel ?

6 speed freewheel with a Shimano Tourney, Shimano Acera X front mech.

 

[Spokesmann]

At Eroica this year...

 

[widowmaker]

Re:

So I could replace my 7 speed 13-28 screw on freewheel with a 14-34, bung on a tourney I have in the shed. I could keep my 52/36 crank. Giving me a 36-34 lowest gear

What's the last ratio before the 34T, I assume there is quite a big jump between gear 5 & 6 ?

The only issue would be my 7 speed indexed downtube shifters, but then I could use them in the friction setting or have a 'ghost' click on them :? :?:

 

[pigman]

Re:

Would have to be in friction mode, no ghost click method. 6 speed is 5.5mm between cogs, 7 speed is 5mm.
However my tricolour 7 speed levers came with a plastic insert that you put in the lever's cable slot to alter the pull ratio for 6 speed

 

[widowmaker]

Re: Re:

Would have to be in friction mode, no ghost click method. 6 speed is 5.5mm between cogs, 7 speed is 5mm.
However my tricolour 7 speed levers came with a plastic insert that you put in the lever's cable slot to alter the pull ratio for 6 speed

Thanks, useful info I may need to keep an eye out for some.

Friction would be ok for me for now, its a training bike and just used for solo rides but its hilly in Dorset :shock:

Am I right in assuming I would need a longer chain for the 14-34 freewheel if I used the 6 speed Tourney rear mech ?

EDIT just found on Spa Cycles they do a SHIMANO 7 Speed TZ31 Megarange Freewheel 14-34, so I could keep my 7 speed indexed 105 DT shifters with a 6/7 compatible Tourney TX35 Derailleur, I just assume I will need a longer chain ??

 

[pigman]

Re:

Just to add, I have used campag 8 speed ergos successfully with a 6 speed shimano back end. Worked perfect, no mods.

 

[widowmaker]

Re:

Thanks for your help Pigman !!

 

[Nob]

What’s wrong with a 14-34 freewheel....just need a rear mech with long cage

I didn't think you could get screw on freewheels with 34 teeth ?

When I was going to college 79/80 I had a 14-34 5 speed block couple with a single 68T chainring upfront on my Carlton Clubman back then. Used a Sun Tour VGT rear mech & ran smoothly. Always got a lot of looks because of the large ring

 

[Spokesmann]

Re: Re:

So I could replace my 7 speed 13-28 screw on freewheel with a 14-34, bung on a tourney I have in the shed. I could keep my 52/36 crank. Giving me a 36-34 lowest gear

What's the last ratio before the 34T, I assume there is quite a big jump between gear 5 & 6 ?

The only issue would be my 7 speed indexed downtube shifters, but then I could use them in the friction setting or have a 'ghost' click on them :? :?:

28 is the 5th gear sprocket.

 

[mattsccm]

If you are running down tube levers then almost any old mech will work as long as it is long enough to cope with the chain length of a wide range of sprockets. Even if indexing or using STI you can mix and match road and MTB up to and including 9 speed. Older Shimano MTb mechs are just junk value. Buy a scrapper MTB and strip it.
Why not fit a MTB chainset?
Older front mechs are much more forgiving than new ones. My Campag Record one works quite happily with a 22/32/42 triple for example.