Minimum wall thickness for triple clamps...

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Yoniboi
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Minimum wall thickness for triple clamps...

Post by Yoniboi »

I know it's a tricky question, but my Spondon lower triples are for a 54mm fork tube (USD) and I want to fit a 56mm fork. Of course I've thought of just getting them machined out by 1mm but I don't want to risk my neck in the process.
Current wall thickness is 7mm, so they'd end up at 6mm. (That'd be a 6mm strip of aluminium running around the fork leg, by 31mm high).
The triples on the RWU fork on the '90 EXUP are 4mm bevelled to 5mm in the middle, but of course the fork is flexier and may??? as such exert less stress on the triple, but still, that suggests there's room for manouver.

Your opinions are eagerly anticipated.
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Hooligan
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Post by Hooligan »

is that 7mm at the thinnest point (i am assuming the outside portion of the clamp)?

i think you'lll be fine. if ya like, i can measure the amount of material on a set of Attack Racing triples to compare.
Jason, aka: Hooligan
1994 YZF750-R
1996 YZF750-R
2003 Bonneville T100

Yoniboi
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Post by Yoniboi »

Thanks Hooli,

Yeah, 7mm at the thinnest point (the bit that actually wraps around the fork leg), which would, after machining, end up at 6mm.

My guess is that the attacks will be something similar... 7mm. The height muct affect things too, more material, so if you could measure the thickness and the height so I've got more comparisons.

Would someone measure the standard YZF or later FZR USD lower triple too please?

Thanks
John
If you're going to take a shot at me let me know so I can duck...!

Hooligan
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Post by Hooligan »

john, i can measure the Attack triples and stock yzf750 triples for ya tonight. i'll post height and thickness.
Jason, aka: Hooligan
1994 YZF750-R
1996 YZF750-R
2003 Bonneville T100

Yoniboi
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Post by Yoniboi »

Cheers Hooli, I'm driving my girlfriend insane with 'qucik checks' on the forum! That should sort it. Thanks

John
If you're going to take a shot at me let me know so I can duck...!

spook
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Post by spook »

Yoniboi wrote:I'm driving my girlfriend insane with 'qucik checks' on the forum! John
Just schedule check-ins between shags, when your girl is reclined, relaxed and smoking a cigarette?

Hooligan
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Post by Hooligan »

ok, measurements as promised. these were taken with a set of digital calipers, so should be pretty darn accurate.

stock yzf750 lower triple clamp
height: 36mm
thickness: 7mm in the center that tapers to 5mm at the top and bottom of the clamp. it's cast that way with a rough parting line right at the center of that lower clamp.

attack performance lower triple clamp
height: 56.5mm
thickness: 5.5mm at the thinnest point

the attack also uses a three pinch bolt arrangement on the lower, the stock uses two.

let me know if you need anything else.
Jason, aka: Hooligan
1994 YZF750-R
1996 YZF750-R
2003 Bonneville T100

spook
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Joined: Mon Jan 29, 2007 7:12 pm
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Post by spook »

6ml will be tons... and would hold them literally. Being spondon they would be billet? Chord more so than thickness is the major determinate... they won't flex so much where the fork is (clamped) attached, it will be mainly between there and the spigot, so what you have will not be greatly affected, if that makes any sense?

Yoniboi
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Post by Yoniboi »

4.48am Hooli.... you need to spend less time in the shed!
Funny how after all these years I still get caught out by the 'international'ness of the 'hood. Wonder what time it was for you when you posted that?
Anyway, back to the important stuff...
Thanks for the info!
Nice to know the Attacks are thinner still, but they are nearly twice the height and I wonder how much that affects the strength?

Right now I think I am going to get them bored out.

Spook, you've been on the beer again? 6ml you say... you want me to melt the triples before I measure them? :) :poke but what you say makes sense, and your ideas are always more than welcome (if open to ridicule!)!!! Yeah, the Spondons are billet, but only 31mm high (read: thick)....

Cheers all,
John
If you're going to take a shot at me let me know so I can duck...!

spook
Dolphin-headed purple plasma TLR thing?
Posts: 3837
Joined: Mon Jan 29, 2007 7:12 pm
Location: Melbourne. Australia

Post by spook »

Yoniboi wrote:Spook, you've been on the beer again?
Ummm, there is no time when I'm off it...
Yoniboi wrote: and your ideas are always more than welcome (if open to ridicule!)
Sure... Cheers... :)

spook
Dolphin-headed purple plasma TLR thing?
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Joined: Mon Jan 29, 2007 7:12 pm
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Post by spook »

Hey thanks Yoniboi, ignorance is not a quality I admire in anyone especially myself :oops:

mm= millimeter... ml= milliliter... Learning every day... Cheers :)

Hooligan
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Post by Hooligan »

ha! it was shortly after 11:00 EDT here in the states. i'm a night-owl anyhow, and i spent the earlier part of the night getting some maintenance items taken care of on the bonnie.

the attacks are very tall, which i think compensates for the slightly thinner walls. i guess it depends on the engineer doing the design, i have seen many aftermarket triples that use a shorter/thicker lower, a taller/thinner lower, and some that use an upper/lower combo that look identical in height.

i think you'll be a-ok milling out the spondons, they make great stuff to begin with.
Jason, aka: Hooligan
1994 YZF750-R
1996 YZF750-R
2003 Bonneville T100

Yoniboi
Help!!! I need a LIFE!!!
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Post by Yoniboi »

Cheers guys,

I'll try and get them done on Monday before the country closes down for Easter.

J
If you're going to take a shot at me let me know so I can duck...!

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