SRAM 7-speed MTB... twist ---> trigger?

DougC said:

A friend recently bought a cheap MTB.
It has a 7-speed external rear end, and grip-shifters, which he has
already found are a pain because they tend to shift inadvertently when
one grabs the bars very hard.

I found some TRX 7-speed triggers on Amazon-http://www.amazon.com/Sram-7-Speed-Trigger-Mountain-Shifter/dp/B0015X...

but I don't know if there was more than one ratio used for MTB shifters.
I know that the /usual/ for them now is 1:1.

The SRAM site only shows the SX4 shifter in 8/7 speeds-http://www.sram.com/en/srammountain/components/sx4/triggershifter.php
-and says they are 1:1. It doesn't mention the TRX ones at all, but
perhaps they don't list all the OEM stuff. And the only 7-speed
grip-shifter they show also gives a 1:1 ratio....

I asked him for a link to the exact bike he got, but I don't have that yet.

Is this the shifters to get or not? So far I haven't run across any SRAM
7-speed shifters that were anything but 1:1.

Depends on the rear derailleur. SRAM rear derailleurs, currently, are
1:1, so you'd need a 1:1 shifter to go with it. Not sure if they
might have done 2:1 derailleurs in the past. Shimano are 2:1, so
you'd need 2:1 shifters if that's what's on the bike.

8-speed shifters work fine on 7-speed cassettes, so your choices
aren't too limited - just match up the top end so that the shifter
goes from 2 to 8. I have SRAM Attack shifters on one bike (2:1) and
Shimano Alivio on another (also 2:1) and both work fine.

Colin

Colin MacDonald said:

Depends on the rear derailleur. SRAM rear derailleurs, currently, are
1:1, so you'd need a 1:1 shifter to go with it. Not sure if they
might have done 2:1 derailleurs in the past. Shimano are 2:1, so
you'd need 2:1 shifters if that's what's on the bike.

8-speed shifters work fine on 7-speed cassettes, so your choices
aren't too limited - just match up the top end so that the shifter
goes from 2 to 8. I have SRAM Attack shifters on one bike (2:1) and
Shimano Alivio on another (also 2:1) and both work fine.

Colin

I did find this one that is 2:1....
http://www.bikepartsusa.com/bikeparts/item/01-130120/shifter-mountain/Pyramid%2D%2DHB%2DATB%2DR%26L%2D3x7%2C%2DwBRAKE%2DLVRS%2C%2DShifter&category=shifter-mountain
Item "Pyramid HB ATB R&L 3x7, w/BRAKE LVRS, Shifter" at bikepartsusa

Hmmm....
~

DougC said:

Colin MacDonald said:

Depends on the rear derailleur. SRAM rear derailleurs, currently, are
1:1, so you'd need a 1:1 shifter to go with it. Not sure if they
might have done 2:1 derailleurs in the past. Shimano are 2:1, so
you'd need 2:1 shifters if that's what's on the bike.

Quoted message said:

8-speed shifters work fine on 7-speed cassettes, so your choices
aren't too limited - just match up the top end so that the shifter
goes from 2 to 8. I have SRAM Attack shifters on one bike (2:1) and
Shimano Alivio on another (also 2:1) and both work fine.

Quoted message said:

Colin

I did find this one that is 2:1....http://www.bikepartsusa.com/bikeparts/item/01-130120/shifter-mountain...
Item "Pyramid HB ATB R&L 3x7, w/BRAKE LVRS, Shifter" at bikepartsusa

Hmmm....

A couple of things to note. If the plan is to replace only the gear
shifters then there's little to be gained in also replacing the brake
levers - the Pyramid shifters are combined brake & gear models. But
if you do go down that road then note that the Pyramid shifters are
for cantilever brakes. If the bike has cantilever brakes then it'll
be OK, but if the bike has V-brakes then the Pyramid units won't work.

If the budget is tight (and I'll assume it is, since that would be the
only reason to consider the Pyramid units) then the Shimano HB SL-
TX30, TOURNEY 3x7 PR shifters on the same page at bikepartsusa will do
the job at $14.99, and saves worrying about brake issues because you
don't need to touch the brake levers. But I'd recommend going for the
Shimano STX/Alivio, SL-MC40, 3x7 shifters (same page again) for $26.
They are a big improvement over the others.

One last thing: the twist shifters occupy a fair bit of handlebar real
estate, so some replacement grips might be needed to cover up the
expanse of metal that is revealed.

Colin

DougC said:

A friend recently bought a cheap MTB.
It has a 7-speed external rear end, and grip-shifters, which he has
already found are a pain because they tend to shift inadvertently when
one grabs the bars very hard.

I found some TRX 7-speed triggers on Amazon-
http://www.amazon.com/Sram-7-Speed-Trigger-Mountain-Shifter/dp/B0015XFPP6/ref=sr_1_1?ie=UTF8&s=sporting-goods&qid=1212658939&sr=1-1

but I don't know if there was more than one ratio used for MTB shifters.
I know that the /usual/ for them now is 1:1.

The SRAM site only shows the SX4 shifter in 8/7 speeds-
http://www.sram.com/en/srammountain/components/sx4/triggershifter.php
-and says they are 1:1. It doesn't mention the TRX ones at all, but
perhaps they don't list all the OEM stuff. And the only 7-speed
grip-shifter they show also gives a 1:1 ratio....

I asked him for a link to the exact bike he got, but I don't have that yet.

Is this the shifters to get or not? So far I haven't run across any SRAM
7-speed shifters that were anything but 1:1.

SRAM produces both their "ESP" series (1:1 as you noted) and "SIS"
series (Shimano compatible)in most models.
--
Andrew Muzi
<www.yellowjersey.org/>
Open every day since 1 April, 1971
** Posted from http://www.teranews.com **

Colin MacDonald said:

If the budget is tight (and I'll assume it is, since that would be the
only reason to consider the Pyramid units) then the Shimano HB SL-
TX30, TOURNEY 3x7 PR shifters on the same page at bikepartsusa will do
the job at $14.99, and saves worrying about brake issues because you
don't need to touch the brake levers. But I'd recommend going for the
Shimano STX/Alivio, SL-MC40, 3x7 shifters (same page again) for $26.
They are a big improvement over the others.

One last thing: the twist shifters occupy a fair bit of handlebar real
estate, so some replacement grips might be needed to cover up the
expanse of metal that is revealed.

Colin

Well, nevermind.

It ends up the rear derailler is a Shimano anyway, with a twist-grip
branded "Echo" (he tells me).
http://www.walmart.com/catalog/product.do?product_id=2061606
and he said something about the grips being junk anyway.

Thanks all-
~