|
|
Thread Tools | Display Modes |
#1
|
|||
|
|||
Rubbing in 24th gear (small chainring, large cog) but frontderailleur is already up against the seat tube.,
I was adjusting the gears on my wife's road bike. It has Shimano Sora
derailleurs. When the chain is on the largest cog in the rear, and the small chain ring (it's a 3 x 8), the chain rubs slightly on the inner plate of the front derailleur cage. But I can't adjust the front derailleur any further, it's already hitting the seat tube. Should I change the bottom bracket to one that has a spindle that's a couple of mm longer to move the chain further out? I'm wondering if they used the wrong length spindle. The issue is I only need another 2mm or so but the longer spindles are about 10mm longer. |
Ads |
#2
|
|||
|
|||
Rubbing in 24th gear (small chainring, large cog) but frontderailleur is already up against the seat tube.,
On 29/04/2016 2:41 PM, sms wrote:
I was adjusting the gears on my wife's road bike. It has Shimano Sora derailleurs. When the chain is on the largest cog in the rear, and the small chain ring (it's a 3 x 8), the chain rubs slightly on the inner plate of the front derailleur cage. But I can't adjust the front derailleur any further, it's already hitting the seat tube. Should I change the bottom bracket to one that has a spindle that's a couple of mm longer to move the chain further out? I'm wondering if they used the wrong length spindle. The issue is I only need another 2mm or so but the longer spindles are about 10mm longer. Would it be ridiculous to suggest putting 2mm worth of shims under the lip of the drive-side bottom bracket cup? I have often done this to move a chain line slightly on a SS drivetrain. https://www.universalcycles.com/shop...ls.php?id=2241 is one of my regular online dealers who stocks them. PH |
#3
|
|||
|
|||
Rubbing in 24th gear (small chainring, large cog) but frontderailleur is already up against the seat tube.,
On Friday, April 29, 2016 at 12:41:43 AM UTC-4, sms wrote:
I was adjusting the gears on my wife's road bike. It has Shimano Sora derailleurs. When the chain is on the largest cog in the rear, and the small chain ring (it's a 3 x 8), the chain rubs slightly on the inner plate of the front derailleur cage. But I can't adjust the front derailleur any further, it's already hitting the seat tube. Should I change the bottom bracket to one that has a spindle that's a couple of mm longer to move the chain further out? I'm wondering if they used the wrong length spindle. The issue is I only need another 2mm or so but the longer spindles are about 10mm longer. You can buy a spacer that fits between the drive side cup and the bottom bracket then screw the non-drive side c up in further. |
#4
|
|||
|
|||
Rubbing in 24th gear (small chainring, large cog) but front derailleur is already up against the seat tube.,
On Thu, 28 Apr 2016 21:41:39 -0700, sms
wrote: I was adjusting the gears on my wife's road bike. It has Shimano Sora derailleurs. When the chain is on the largest cog in the rear, and the small chain ring (it's a 3 x 8), the chain rubs slightly on the inner plate of the front derailleur cage. But I can't adjust the front derailleur any further, it's already hitting the seat tube. Should I change the bottom bracket to one that has a spindle that's a couple of mm longer to move the chain further out? I'm wondering if they used the wrong length spindle. The issue is I only need another 2mm or so but the longer spindles are about 10mm longer. What kind of bottom bracket? The Shimano "outboard bearing" BB uses "plastic washers" as shims to adjust the chain ring position. -- Cheers, John B. |
#5
|
|||
|
|||
Rubbing in 24th gear (small chainring, large cog) but frontderailleur is already up against the seat tube.,
|
#6
|
|||
|
|||
Rubbing in 24th gear (small chainring, large cog) but frontderailleur is already up against the seat tube.,
On Friday, April 29, 2016 at 7:37:56 AM UTC-4, wrote:
raise/lower deray or http://www.toolup.com/product-images/Vise-Grip-23_1.jpg use 2 ( or more!) always...one holds one bends. deray metal still malleable ? |
#7
|
|||
|
|||
Rubbing in 24th gear (small chainring, large cog) but frontderailleur is already up against the seat tube.,
On Friday, April 29, 2016 at 7:39:52 AM UTC-4, wrote:
On Friday, April 29, 2016 at 7:37:56 AM UTC-4, wrote: raise/lower deray or http://www.toolup.com/product-images/Vise-Grip-23_1.jpg use 2 ( or more!) always...one holds one bends. deray metal still malleable ? knuck knuck .....also poss drill out cage's end rivet n rebolt with appropriate red locktited/nylock fastener |
#8
|
|||
|
|||
Rubbing in 24th gear (small chainring, large cog) but frontderailleur is already up against the seat tube.,
On 4/28/2016 9:59 PM, Peter Howard wrote:
On 29/04/2016 2:41 PM, sms wrote: I was adjusting the gears on my wife's road bike. It has Shimano Sora derailleurs. When the chain is on the largest cog in the rear, and the small chain ring (it's a 3 x 8), the chain rubs slightly on the inner plate of the front derailleur cage. But I can't adjust the front derailleur any further, it's already hitting the seat tube. Should I change the bottom bracket to one that has a spindle that's a couple of mm longer to move the chain further out? I'm wondering if they used the wrong length spindle. The issue is I only need another 2mm or so but the longer spindles are about 10mm longer. Would it be ridiculous to suggest putting 2mm worth of shims under the lip of the drive-side bottom bracket cup? I have often done this to move a chain line slightly on a SS drivetrain. https://www.universalcycles.com/shop...ls.php?id=2241 is one of my regular online dealers who stocks them. PH Thanks, I wasn't aware of these shims. This should work. I might get by with jut one of those 0.7mm shims. I had thought of putting a thin washer on the end of the drive side spindle but didn't think that that would be a good idea. |
#9
|
|||
|
|||
Rubbing in 24th gear (small chainring, large cog) but frontderailleur is already up against the seat tube.,
On 4/28/2016 9:41 PM, sms wrote:
I was adjusting the gears on my wife's road bike. It has Shimano Sora derailleurs. When the chain is on the largest cog in the rear, and the small chain ring (it's a 3 x 8), the chain rubs slightly on the inner plate of the front derailleur cage. But I can't adjust the front derailleur any further, it's already hitting the seat tube. Should I change the bottom bracket to one that has a spindle that's a couple of mm longer to move the chain further out? I'm wondering if they used the wrong length spindle. The issue is I only need another 2mm or so but the longer spindles are about 10mm longer. If the shimming others suggested doesn't work to your satisfaction, you can look to see the nature of the FD portion that is hitting the seat tube. If it's not structural (or could still serve its structural purpose after filing), file/Dremel it down a mm or two. This is touchy and should be done with care, but I've successfully done it on at least two Campy FDs (triple with smaller-than-spec small chainring), with no failure thousands of miles / many shifts later. Mark J. |
#10
|
|||
|
|||
Rubbing in 24th gear (small chainring, large cog) but frontderailleur is already up against the seat tube.,
Should I change the bottom bracket to one that has a spindle that's a
couple of mm longer to move the chain further out? I'm wondering if they used the wrong length spindle. The issue is I only need another 2mm or so but the longer spindles are about 10mm longer. I solved a similar problem on my touring bike by putting in a longer bottom bracket. Shimano sealed bearing kind. Square taper. I was able to find one that was just barely long enough. Not too long. I thought Shimano made many different length bottom brackets. Every 1 or 2 mm between about 100 and 150. |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
FA: Small Arm Warmers, Small and Large Aero Booties | carnivore | Marketplace | 0 | October 4th 05 04:38 PM |
WTB: Cross bike, approx 51 seat tube, 53 top tube. | the catfish | Marketplace | 0 | May 8th 05 05:45 PM |
Compact front derailleur on large diameter seat tube | Techniques | 5 | May 1st 05 03:15 AM | |
Seat rubbing a hole in my pants | B.B. | Techniques | 20 | October 4th 04 05:44 PM |
Frame Size: Go Large or Small? | Simonb | UK | 5 | May 28th 04 04:39 PM |