Revoshift to TX50 conversion

thelonegroover

My daughters bike has 7 speed Shimano Tourney rear gears with the twist revoshifters, I'd like to upgrade the shifters to TX50 thumb shifters, are these a straight replacement and can I use the existing cables?

Andy B

straight replacement for the shifters

You will also need new bar grips as the revoshift use a half grip IIRC

Best to use new cables, but you could use the old ones if they're in good condition & not frayed.

thelonegroover

I can see the right hand rear 7 speed index is a straight replacement. However I now find there are two left hand three speed options, index or friction. The front mech on this bike is Shimano SIS, which I'm guessing is index.

My local Halfords advised me to go for the index version regardless, however another local shop said it depended on the chain set. I have no idea what chain set is fitted.

My questions are: 1. How do I know if I need the index or friction version and 2. Will either work. The 7 speed shifter seems to have a separate release button for changing up, but neither of the 3 speed shifters have?

Not sure if this link will work, but here goes...

http://techdocs.shimano.com/media/techd ... 667407.pdf

PBo

isn't the current twist shifter effectively indexed? Maybe I misunderstand, but all indexing is controlled at the changer, not the derailleur? (Although I guess there is the actuation ratio issue....)

thelonegroover

PBo wrote:

isn't the current twist shifter effectively indexed? Maybe I misunderstand, but all indexing is controlled at the changer, not the derailleur? (Although I guess there is the actuation ratio issue....)

I thought so, but there must be some difference or why would Shimano make two versions?

night_porter

As your derailler has SIS on it then (as you quite rightly say) you need to use the indexed shifter not the friction one for the left hand. A quick look at replacement chains and you will see that most chains to fit a 7 speed are so universal that they also fit 6 & 8 speed so I would suggest that you would be safe to not worry about the size of the chain.

As far as the dual changer on the right is concerned I think you will find that when you change down (larger sprocket at the back) your thumb is not only moving the chain it is also compressing the spring in the rear derailler. Conversely when you change up the spring is assisting your efforts because it is trying to return to it's resting position. This reduced effort means that it is possible to put a second "button" (as opposed to the lever on the model in the picture) for shifting.

I have replaced twist grips on a couple of bikes and been extremely pleased with the results but I have one word of warning. I tried to do the same on my daughters bike (she is only 10) and she hated the thumb shifters. The reason for this was the amount of pressure required by her right hand thumb was too much for her, with the twist grips she is able to use her whole hand to make the shift and at her age it is much easier.

Finally, are you happy to setup your rear derailler? I only ask because changing the shifters means that you have to reconfigure it, not from scratch as the limit screws won't have changed but the cable adjustment will need to be done. Sorry if you already knew that but I thought it best to point it out.

Good luck with the job!

thelonegroover

Hi Night Porter,

Thanks for your reply. My wife is getting a new bike so daughter who is nearly 13 will be getting this one. Both daughter and son (11) want thumb shifters.

I'll fit them to this bike and then see if they suite my him.

I have no problem adjusting the mechs front or rear.

thelonegroover

Andy_B wrote:

straight replacement for the shifters

You will also need new bar grips as the revoshift use a half grip IIRC

Best to use new cables, but you could use the old ones if they're in good condition & not frayed.

The new shifters actually come complete with new cables. £7.99 each, which I thought was excellent value.

Wilkovian

Thelonegroover wrote:

My daughters bike has 7 speed Shimano Tourney rear gears with the twist revoshifters, I'd like to upgrade the shifters to TX50 thumb shifters, are these a straight replacement and can I use the existing cables?

Hi, so it's obviously a super-old thread but did you manage this? I have an old Trek Gary Fisher Alfresco that I've been using as a cheap and cheerful tourer (chromalloy frame handles 4 full panniers' weight surprisingly well for an old machine!) but it has an old set of Revoshift 3x7s on it and I want to change the handlebars anyway so was thinking of converting to TX50s. I don't have a lot of bike mechanic experience though so it's a learning as I go situation.

Did this conversion work out in the end? How difficult was it did it require a lot of tuning?