More about gears.. actuation ratio?

[morphix]

What's the deal with "actuation ratio" on derailleurs? Some have 1:1 and some have 2:1, different standards, some hardware is incompatible with others eh?

So which is best for actuation ratio? And what does it mean in real terms?

I'm looking at short cage derailleurs for my Mezzo, seen this Sunrace one on eBay, dunno if anyone has any good/bad experiences or things to say of it?

The only thing that annoys me about folding bikes is the hanging derailleur and chain with oil on my best clothes. I've ruined 2 pairs of jeans already I wish there was an alternative to derailleur (yeah I know, hub gears, but not with rear wheel drive motor eh). Maybe there's some solution to cover it or stop oil rubs?

 

[morphix]

Ha,I just saw this derailluer coat

 

[Scimitar]

Snazzy.
From what I've found it only matters if you're index shifting and synchronicity goes out the window twixt bar and arrs-end. I cunningly got around that by using a friction shifter.

 

[morphix]

Another one, I like Shimano they been around along time..

Shimano Tourney RD-FT30 Tourney Short Cage Rear Derailleur

This one is shortest in their range and claims to be recommended for 16" wheels. Same price as Sunrace one above, £9.

 

[Deleted member 4366]

The shifter, derailleur and free-wheel set all need to be able to handle the number of gears, i.e. 7-speed free-wheel. 7 or more speed derailleur, 7-speed shifter. Those Shimano Tourney oones are OK, but you have to make sure you get the right fitting to fix it to your frame. There's more than one version. Do you have a hanger on your frame?

 

[morphix]

The shifter, derailleur and free-wheel set all need to be able to handle the number of gears, i.e. 7-speed free-wheel. 7 or more speed derailleur, 7-speed shifter. Those Shimano Tourney oones are OK, but you have to make sure you get the right fitting to fix it to your frame. There's more than one version. Do you have a hanger on your frame?

I'm not sure Dave and this is a good point you make I didn't realise.. I will take some pics later and post up. I have 9-spd at moment but I'm downgrading to 7-spd... I expect to change the shifter, but maybe my derailleur could stay, but I was thinking the shorter one might be better for not hanging so low and lighter weight a bit.

 

[catsnapper]

D8veh is correct about the 2 fittings on the Tourney units, one is for conventional hangers, the other is for frames without a hanger - both types are sold here Shimano TX35 Tourney 6-7 Speed Rear Mech

Your bike uses a normal hanger, like most modern bikes. The other thing to watch out for with short cage units is having enough capacity to cover a 28t cog, most but not all do.

If you start mixing makes of freewheel and derailleur away from either Shimano compatible parts or whatever manufacturer you choose, changes will become haphazard at best. As Scimitar says, friction change will be your only choice - ok for us older riders that grew up with it, but not exactly a forward move

Depending what 9spd cassette, derailleur and shifter you have, you may not need to change the derailleur, only the shifter. Compatibility is not always what it seems.......

Alan

 

[morphix]

D8veh is correct about the 2 fittings on the Tourney units, one is for conventional hangers, the other is for frames without a hanger - both types are sold here Shimano TX35 Tourney 6-7 Speed Rear Mech

Your bike uses a normal hanger, like most modern bikes. The other thing to watch out for is short cage units have enough range to cover a 28t cog, most but not all do.

If you start mixing makes of freewheel and derailleur away from either Shimano compatible parts or whatever manufacturer you choose, changes will become haphazard at best. As Scimitar says, friction change will be your only choice - ok for us older riders that grew up with it, but not exactly a forward move

Depending what 9spd cassette, derailleur and shifter you have, you may not need to change the derailleur, only the shifter. Compatibility is not always what it seems.......

Alan

Thanks Alan, I'll take some pics and find out all the existing parts and then we can decide which parts can stay and which need to go.. I'm thinking if I do change, to keep everything Shimano (which is the existing brand used on bike and I know works well) and I can use the SIS index shift system...assuming that will work with the DNP 7-spd 11-28 freewheel. At least these parts are not expensive so won't be a prob if it doesn't work, just the hassle of fitting and unfitting.

 

[morphix]

Mezzo D9 gears photos

Hi guys,

Took me a while to around to it, but here's the derailleur photos for my Mezzo D9.. hopefully someone will be able to advise me better on whether the two above derailleurs are suitable or something else (for a 7-spd 11-28T freewheel)? Also any info on a compatible shift would be useful, assuming I'll need to replace the current 9-spd SRAM (see last photo)... excuse the photo quality bit dark in my hallway so had to brighten these up.

 

[morphix]

The only information I can gleen about which precise parts are used is from the Mezzo manufacturers spec on the website which states:

Shifter: SRAM Attack
Rear Derailleur: Shimano Tiagra

 

[catsnapper]

The Tiagra derailleur should be ok with your new freewheel as long as it has Shimano compatibility. The shifter simply needs changing to a Shimano 7spd.
The Tiagra is a decent mid range unit, the Tourney units work well, but are not the same quality. Unless you want to change for cosmetic reasons....

Not all so called Shimano 'compatible' freewheels and cassettes are as compatible as you'd expect....although they're usually workable.
I currently use a Tiagra on a 7spd 11-28t cassette without any problems.

Alan

 

[morphix]

The Tiagra derailleur should be ok with your new freewheel as long as it has Shimano compatibility. The shifter simply needs changing to a Shimano 7spd.
The Tiagra is a decent mid range unit, the Tourney units work well, but are not the same quality. Unless you want to change for cosmetic reasons....

Not all so called Shimano 'compatible' freewheels and cassettes are as compatible as you'd expect....although they're usually workable.
I currently use a Tiagra on a 7spd 11-28t cassette without any problems.

Alan

Thanks Alan, I'll see how it goes then before any spend any money on the Tourney I do like the shorter one and way it looks, but not if it comes at a performance cost and less smooth gear changing ;-) I'll see if I can find a Shimano 7-spd that's similar design with the 2 levers.. I prefer that to the twist ones.

 

[catsnapper]

I think I mentioned that I've got a decent, spare Shimano 7spd 2 lever shifter Depending on your handlebar setup which type of shifter suits. Some have the levers below the bar, the simpler Tourney button/lever shifters are above the bar and avoid hitting throttles etc....

Alan

 

[morphix]

I think I mentioned that I've got a decent, spare Shimano 7spd 2 lever shifter Depending on your handlebar setup which type of shifter suits. Some have the levers below the bar, the simpler Tourney button/lever shifters are above the bar and avoid hitting throttles etc....

Alan

Oh yes I forgot. If you can send it I will probably have it then..how much do they cost? I hope my freewheel arrives this week!