gt rts main frame bushing modification

[Peteroughton169]

hi all, anyone modified the main pivot to use a sealed bearing rather than the bushing? if so what did you use?

 

[ishaw]

It's not really a mod as such, mine came with a bushing. I can dig out the bearings I have, as one of my frames is not built as going to paint it.

I do have some NOS top hat bushings too.

 

[Peteroughton169]

i measured with calipers the bushing, and came out at bearing equivalent of 9x20x9. nearest ive found is 9x20x6. a mate can machine a spacer of 3mm each side, but wouldnt it need a central spacer also to stop the bearing inner race binding when the pivot bolt is tightened?

 

[Peteroughton169]

i assume you'll be holding onto the nos bushings!

 

[ishaw]

There is indeed a central spacer. I didn't get time this evening but I can dig out the parts you need.

As for the top hats, both my frames have bearings so technically I don't need them.

 

[ishaw]

I found a few pics on my phone. Top hats still in packet and a group shot including the bearings. I've forgotten the name/type but they aren't standard sealed ones, the centres can pivot/move and sit proud of the outer casing.

I'll measure the bits tomorrow.

 

[Peteroughton169]

I found a few pics on my phone. Top hats still in packet and a group shot including the bearings. I've forgotten the name/type but they aren't standard sealed ones, the centres can pivot/move and sit proud of the outer casing.

I'll measure the bits tomorrow.

that would be great, I'd be interested in the tophat bushings if you're willing to let them go too

 

[ishaw]

Sorry for the delay, been a hectic week for various reasons. I've grabbed some pics of the main pivot bearings I have currently out of a frame, including what I hope are useful shots of measurements and markings that might indicate the part number of the bearings and spacer size. My callipers aren't working so manual size indication only, and they wouldn't fit inside the bearing or spacer so I can't give an accurate inner diameter.

Better pic of top hat bushings too, which I guess I'd be willing to part with.

Hope it's useful.

 

[Splatter Paint]

That is a spherical plain bearing. Looks like chrome / ptfe. I just ordered some from McGill Motorsport for my bike.

You need the ball width, cage width, bore id and cage of to order some. There are metric and imperial versions.

 

[Peteroughton169]

Sorry for the delay, been a hectic week for various reasons. I've grabbed some pics of the main pivot bearings I have currently out of a frame, including what I hope are useful shots of measurements and markings that might indicate the part number of the bearings and spacer size. My callipers aren't working so manual size indication only, and they wouldn't fit inside the bearing or spacer so I can't give an accurate inner diameter.

Better pic of top hat bushings too, which I guess I'd be willing to part with.

Hope it's useful.

thankyou thats great info