Lower Gearing Options

[jcostanz]

I have a lwb recumbent. I need to lower the gearing on it for hills. Right now with the stock Shimano 105 Crank, 52 39 30, and a Delore LX front derailer, the chain ocasionaly rubs the bottom of the front derailer when in granny gear and there is almost no room to move the derailer down, it would hit the outer chain ring.

What are my options to lower the gearing? I know that switching to a mountain crankset is one. I would like to just switch chain rings but the derailer doesn't seem to allow greater than a 22 tooth difference in chain rings and the middle chain ring is as about as small as I can get it, 130 mm bcd. ps I have bar end shifters, ie friction front.

Thanks
Jeff

 

[martin_j001]

What size cassette are you running? Not sure if its an option to change that out or not for you, but its worth looking into.

 

[boudreaux]

I have a lwb recumbent. I need to lower the gearing on it for hills. Right now with the stock Shimano 105 Crank, 52 39 30, and a Delore LX front derailer, the chain ocasionaly rubs the bottom of the front derailer when in granny gear and there is almost no room to move the derailer down, it would hit the outer chain ring.

What are my options to lower the gearing? I know that switching to a mountain crankset is one. I would like to just switch chain rings but the derailer doesn't seem to allow greater than a 22 tooth difference in chain rings and the middle chain ring is as about as small as I can get it, 130 mm bcd. ps I have bar end shifters, ie friction front.

Thanks
Jeff

That LX FD is not ideal due to the short cage length. A road triple 105 is a better option. You can also use a 24 or 26 granny on that crank with a road FD.

 

[jcostanz]

I had ordered a triple 105 front derailer. The tube that the FD mounts to is too short for Shimano's road derailers. The mounting clamp on the road derailers is above the cage, while on the mountain derailers it is below. The exising derailer is a mega drivetrain, and it looks like the cage is about the same size as the road version.

The rear cassette is a mountain style, around 32 tooth granny


Is there any front derailers out there that have a longer cage?

Thank you for your help

Jeff

 

[gclark8]

Have a look at the Shimano FD-R443 Front derailleur, it is used on road/flat bar mixes, however it mounts above the pivot. I asume the present one is FD-M580 or similar. A FD-CO51, designed for 48-49t down to 26t may be another option, I have used this in MTB/Road conversions.

 

[jcostanz]

Thank you for all your suggestions.

With the angle of the tube that the derailer mounts to, the derailer seems to be sized right for the 52 tooth ring, I assume that this angle is different than standard.

I am trying to find a longer cage derailer. The existing one is a mega drive.
The cause of this problem is a chain pully that is pulling the chain down before the derailer. The pully is required to keep the chain out of the steering mechanism.

If I cannot find a derailer with a longer cage, I will have to change the crankset. This might not even solve the problem.

Thanks

Jeff