How thin can you go on triple clamps?

[tkent02]

Can I bore 35mm clamps to use 37mm fork tubes safely? How thin can you go without making it too weak?

[hampshirehog]

I've done it. I've no idea if it's safe but, to quote the Aussie politician, the front didn't fall off. It seems to me there's plenty of meat on there and it's only 1mm in radius.

[tkent02]

OK. That sounds right. There are four of them holding it together after all. They can't possibly all break at once. Can they? I'm sure Suzuki put at least an extra mm in there just for the what ifs. "What if some twatwaffle hits a lorry? Will the forks break if he hits a lorry?"

Have you taken more than 1mm off and had it not break?

Can any old machine shop do it?

[posplayr]

Can I bore 35mm clamps to use 37mm fork tubes safely? How thin can you go without making it too weak?

No simple answer. Assuming the did a decent job in the design to start with and there is no stress risers then compare the thinnest dimension score and after boring. The 35mm to 37mm bore is only 1mm off on any side so it is probably ok. In general I would not recommend it.

Unfortunately a failure could still mean they all go at once. If one (the weakest) goes suddenly three are now taking the load leading to the next weakest breaking then you are down to two for the same load. You see where I'm going. Under external load, If one goes expect them all to go.

[Steve]

I also find it interesting that you are willing to weaken one area just to make another one stronger.

The larger forks would add to the strength and rigidity of the front end, but might also transmit a bit more shock load to the (now weaker) clamps.

So many of these bikes are still moving around (and quite well) on 35mm forks with no apparent problems. Unless you are setting one up for the extra loads of racing or off-roading, what do you really hope to gain with the larger forks?

I am thinking it might be an exercise in futility.

.

[tkent02]

More room inside to convert it to a cartridge fork. Don't care how it moves, trying to get it to ride smoother.

[hardline_42]

What bike are the donor forks coming from? It seems like it would be much easier to swap over the entire front end, including the triples. GS850G forks are 37mm and so are GS500 forks. They should all use the same steering head bearings. I've got a 41mm SV650 front end in my garage waiting for a future swap onto my GS450.

[mmattockx]

Can I bore 35mm clamps to use 37mm fork tubes safely? How thin can you go without making it too weak?

Depends. How much material is there now with the 35mm forks?

OK. That sounds right. There are four of them holding it together after all. They can't possibly all break at once. Can they?

No, the first one would fail which would overload the next one in line which would fail, then the next and so on.

Can any old machine shop do it?

Most likely. You just need someone with the capacity to line bore both clamps together in one setup to ensure that they are a matched set. Will your pinch bolts clear the bigger fork tube?

What bike are the donor forks coming from? It seems like it would be much easier to swap over the entire front end, including the triples.

That sounds like a much better choice. OP, if you are looking at this to help with the cartridge conversion we discussed I would say that swapping to a complete front end with a modern fork that already has shim stack damping would be much easier. If you want to keep the classic GS look then this may be the better option.


Mark

[tkent02]

This is for my 550. Not interested in swapping forks on this bike. Got the single brake working well, want to keep it how it is. Don't really want to make a lot more work for myself. Considering swapping fork internals to make this fork into a cartridge fork. Going to 37mm would give a little more room inside for the cartridge. I have a set of 37mm forks from a GS1000 sitting here.

Could also swap steering heads, but I think all of the 37mm GS steering heads would put the fork tubes farther apart, again making more work for myself.

[hardline_42]

Could also swap steering heads, but I think all of the 37mm GS steering heads would put the fork tubes farther apart, again making more work for myself.

If that were the case, wouldn't it just require some spacers? If you're going to have machine work done anyway, I think machining spacers would be a safer route to take than boring the clamps.

[tkent02]

If that were the case, wouldn't it just require some spacers? If you're going to have machine work done anyway, I think machining spacers would be a safer route to take than boring the clamps.

Yeah, that's probaby a better plan.

[posplayr]

This is for my 550. Not interested in swapping forks on this bike. Got the single brake working well, want to keep it how it is. Don't really want to make a lot more work for myself. Considering swapping fork internals to make this fork into a cartridge fork. Going to 37mm would give a little more room inside for the cartridge. I have a set of 37mm forks from a GS1000 sitting here.

Could also swap steering heads, but I think all of the 37mm GS steering heads would put the fork tubes farther apart, again making more work for myself.

If you put a flat screw driver into the cut of the clamps, you might be able to open them the amount required to slip the 37mm ones in. When you tighten it down it, the aluminum will "conform" to the steel.

[tkent02]

If you put a flat screw driver into the cut of the clamps, you might be able to open them the amount required to slip the 37mm ones in. When you tighten it down it, the aluminum will "conform" to the steel.

Like that idea a lot better, it seems like it would be stronger, and safer unless something cracks. Any metals experts here? Is that safe to do as long as it doesn't crack? I need to go see how much it would need to be opened up. I have a bunch of spares to practice on.

Thanks for the idea.

[Agemax]

expanding cast aluminium by even that small amount will DRASTICALLY weaken it. That is if it doesn't snap or crack anyway before you manage to shoehorn the fork leg in.

[salty_monk]

Are you sure the 1000 triple clamps are wider? I would think that the centers are the same...