Chain Alignment Challenge

[duane]

Hi,

I have a Base TA26 with a 28 tooth chain ring and an eight speed cassette with a range from 9 to 28 tooth.

The problem is that the chain ring is positioned for perfect chain alignment with the second sproket in on the cassette, this causes real trouble when I have the bike in my trials gear (seventh spoket in) as the chain meets the chain ring at a noticeable angle which I beleive is the cause of the chain dropping off the inside of the chain ring every five minutes.

Obviously there are lots of ways I can fix this by loosing some of my gears, but I find them essential for getting around espcially as I live miles from anywhere, therefore anything that involves loosing either the 9 or the 24 is not a solution.

One bodge I am considering is to put an additional 28 on the front using longer bolts and spacers, I can then shift the chain manually when I get where ever I am going. It might not sound it, but this will be considerably less hassle than having to putting the chain back on every few minutes.

Has anyone tried something similar, is it strong enough ? or are there better solutions that will enable me to keep my current ratios ?

Thanks for any suggestions,

Duane.

[Joe_Elding]

Could you not just take off the first five cogs and then shift the rest up so that your trials gear is 2nd in line and then your cycling gear are still there? and then put spacers at the end.

Or am I being thick?

[duane]

Hi Joe,

Yes, that will fix the aligment but I am guessing it will be asking too much for the rear shifter to cope with a single jump from 9 to 24, I would really like to keep some ability to shift for hills, roundabouts and sand. Having easy access to a sand gear while ridding around is really very important to me, I live in Dubai.

Anyone have any experience of something similar to Joe's suggestion, or what is the maximum increase betweem cogs, ie. can I get away with shifting between 9, 16 and 24 and then just use some washers to move the chain ring in a bit ?

Regards

Duane.

[duane]

Hi All,

Thanks for the replies, as suggested I finally got around to taking my shimano 8 speed cassette apart and moving the sprockets around, I now have 12,13,15,*19*,14,16,17,21 which puts the 19 where I want it for better chain alignment. The gear shift is okay so far. The next plan if tarty every get back to me is to replace the unused 14,15,16,17 and 21 with spacers and change the 19 for a wide based surley.

Cheers

Duane.