Is this safe ??

[sharky]

One for the engineers...

32mm T-bars, 65mm spacers to raise bar height (old shoulder injury getting worse)

http://i419.photobucket.com/albums/pp276/sharkster68/Bars.jpg

I'm making a new set but wanted to test out the idea first...

Oh and No, the top yoke isn't 13mm thick...only the bit where the bolts are...

[Redmohawk]

Easy enough to test, just do it and if you brake it doing an endo its not strong enough !

If you use grade 8 or 10 high tensile bolts they will prob be fine. The bigger issue would be distributing the load through your yokes with a single bolt and 32mm. Do you have room to make a hat for above ( tapered spacer ?) and below the yoke to spread the load over a larger part of the yoke ?

[latheboy]

12.9 bolts is the way forward.

When you say the clamping area is 13mm, whats the thickness in the surrounding area.
If that's only 3mm then forget it.

You'll want 20mm of thread in the bars ....

Like Adam said, if you can spread the load the better you will be.

It will flex, the more you lift it the more it will flex.

[sharky]

The whole top area of the yoke is 13mm.
Its basically a hollowed out 60mm thick billet
Oh and surprisingly......both uprights will have a bolt in them....Doh

[Gix11]

What are the bars and spacers made of? Could you not weld the spacers on for a bit of extra strength and maybe make some sleeves to cover them?

[Redmohawk]

The whole top area of the yoke is 13mm.
Its basically a hollowed out 60mm thick billet
Oh and surprisingly......both uprights will have a bolt in them....Doh

I ment single bolt per side lol

I used twin bolt risers so the load was spread more (about 50mm between centres of bolts each side 8mm high tensile grade 10 bolts) tall 75mm risers and upswept dirt bars (same reason bad back) I used on betty . Bar grips are prob about the same hight above 10mm plate (my top yoke to speek of, as far as bars are concerned) as yours would be . No flex I can feel even when rear wheel is off the ground and my spincter is clentched.

[sharky]

As its only a test I'll see if I can sleeve over the join with a tight fitting tube
I'll also get the biggest diameter washes I can to spread the extra load.
I've been running the 32mm Tbars without any probs so far.

[latheboy]

You also want thick washers.
Thin ones won't do anything.

[Redmohawk]

The 32 mm diam with the standard length risers is no issue , but as you raise the hight of the bars (with the extentions ) you will make a leaver effect (higher the bars , the more effect). Raising the bars by an extra 65mm doesnt look like much, But if the bars are twice as high as they were originally and the diam of the mountings are the same the load will about double. If your 100kg and your stopping at 2g (not a prob with good brakes) thats 200 kg on the bars, times by say 4 taking into account the leaver effect you could be looking at 800 kg on your mounting points the risers.

Hence spreading the load by increasing the diam at the yoke can reduce the leaver effect. A 5mm increase in radius is 10mm bigger diam taking a 32mm to 42 mm (not a big step with a taper) but dividing 42 mm into the hight of your bars instead of 32mm will make a big difference to the outcome.

If you want to lock the bars to the extentions but keep it looking smooth, a 20mm hole bored into the bars 10mm deep and a step machined onto the top of your extentions will lock them together well. Assuming there is enough thread avalable in the bars to be able to loose 10mm.

[ozzy1100]

i have made these up tonight for russ
i taked him into not useing a bolt tho the lot we are useing a stud in the top between riser and bar
i have got some high tention bolts that ill cut the thread off and will end up with 20 mm into each side
with some retaneing comp i dont think it will to bad.
red i was thinking the same as u i had some 44mm mild stock sitting there so cleaned to 43 mm then stepped up 10 and back to 32 at 35* and russ ended up mocking it up and went 60 long so he didnt have to move lines or any new ones it should be good as gold he had to buy a 1/2 unf tap so we will tap them and he can have them poweder coated and you will be hard presed to see they been raised.

[Redmohawk]

Very good shit ! Good for russ. (like the stud idea better than a long bolt to !)

[ozzy1100]

yer that way yr not shareing the load thro the one fixture
i have high tention bolts for the bottom as well and made up 1/4 thick 43 mm washers for the under side of clamp
with out steps i couldnt think of any way to make it stronger

[Redmohawk]

Sounds pritty solid now .

[ozzy1100]

http://i1136.photobucket.com/albums/n493/ozzy1100/lyntonsiphone020600x448.jpg
they will have some hole droped into base so russ can use to do up with out marking powder
he will drill them in the drill press to suit his grinder key as my mill still has to be rebuilt doh

[Hagarr]

The 32 mm diam with the standard length risers is no issue , but as you raise the hight of the bars (with the extentions ) you will make a leaver effect (higher the bars , the more effect). Raising the bars by an extra 65mm doesnt look like much, But if the bars are twice as high as they were originally and the diam of the mountings are the same the load will about double. If your 100kg and your stopping at 2g (not a prob with good brakes) thats 200 kg on the bars, times by say 4 taking into account the leaver effect you could be looking at 800 kg on your mounting points the risers.

Hence spreading the load by increasing the diam at the yoke can reduce the leaver effect. A 5mm increase in radius is 10mm bigger diam taking a 32mm to 42 mm (not a big step with a taper) but dividing 42 mm into the hight of your bars instead of 32mm will make a big difference to the outcome.

If you want to lock the bars to the extentions but keep it looking smooth, a 20mm hole bored into the bars 10mm deep and a step machined onto the top of your extentions will lock them together well. Assuming there is enough thread avalable in the bars to be able to loose 10mm.

And here's me thinking you're a dumb arse Red LOL HAHA. sound thinking, thats what I wa sthinkin, shear is the force here you need to worry about and not surprisingly lots of it!!

[Redmohawk]

they will have some hole droped into base so russ can use to do up with out marking powder
he will drill them in the drill press to suit his grinder key as my mill still has to be rebuilt doh

The grinder key is a great idea , makes loosing mine for the 3rd time an even bigger mistake lol

[Redmohawk]

And here's me thinking you're a dumb arse Red LOL HAHA. sound thinking, thats what I wa sthinkin, shear is the force here you need to worry about and not surprisingly lots of it!!

I is dumb , I just get lucky once and a while. If I can fix it with a mash hammer all's good , if I can't you'll need a new whatever when I'm done anyhow.

[fimpBIKES]

as long as you cant feel too much flex it would be ok

its not like you can bend the bolts by putting your weight fully on the ends of the bars or anything is it?

it would almost definitely bend or fuck your upper triple in a crash, but its not really meant for that

[sharky]

If I crash hard enough to bend these I will have a lot more to worry about than just a set of bars..

[latheboy]

as long as you cant feel too much flex it would be ok You say here, it will flex

its not like you can bend the bolts by putting your weight fully on the ends of the bars or anything is it? Then you say, it won't bend



What drugs are you on? Flex and bend pretty close to the same thing.
The bars are a lever and if you put your full weight on them you will bend the bolts.

[fimpBIKES]

flatbars flex more than clip-ons, its just a matter of how much is reasonable for you
flex is non-plastic deformation, a mm or two max

the force on the bars during normal riding will only have to be enough to move the front wheel off course
no more than a few kilo's. but even if its 50kg it wont bend the bolts with less than 100mm of leverage, and definitely not enough shear force (from front wheel resisting turning force) to worry the bolts

[fimpBIKES]

If I crash hard enough to bend these I will have a lot more to worry about than just a set of bars..
my point exactly, got em fitted yet? :p

[Redmohawk]

flatbars flex more than clip-ons, its just a matter of how much is reasonable for you
flex is non-plastic deformation, a mm or two max

the force on the bars during normal riding will only have to be enough to move the front wheel off course
no more than a few kilo's. but even if its 50kg it wont bend the bolts with less than 100mm of leverage, and definitely not enough shear force (from front wheel resisting turning force) to worry the bolts


Turning forces on a bike are so low its not worth mentioning a 3mm bolt pair would handle those forces , a tank slapper with contact of body parts would be a whole different ball game. Let alone a emergancy stop hard enough to lift the rear wheel 1m in the air ( 1G is about 30 k/h to zero in on second) and an average sports bike will lift the rear wheel off the ground at braking forces over 1.3 G. So a 80kg bloke will excert about 107.5kg on the bars. Ie if you can hang off your bars without bending them its unlikely you will break them riding.

[sharky]

Extensions are at powder coaters...pick 'em up in the morning (good old local bloke..24hr turn around)

As for the hole force/stress/flex thing...T-bars have been around for years...My XS1100 in '92 had 10" T-bars....never had a prob.

[latheboy]

Ok, i thought you were talking about the bolts saying they will flex but shouldn't bend.

[sharky]

http://i419.photobucket.com/albums/pp276/sharkster68/2012-05-03075050.jpg
http://i419.photobucket.com/albums/pp276/sharkster68/2012-05-03143807.jpg
http://i419.photobucket.com/albums/pp276/sharkster68/2012-05-03143737.jpg

Big thanks to Lynton for the parts..nice one mate

[ozzy1100]

just happy to have something with my name on there old boy lol

[xa-mont]

i love the "post and rail" (for want of a better term, makes it sound like a fence) system you have there to hold your cables and whatnot in place.

[Redmohawk]

Great work chaps , looks sweet !

[latheboy]

Nicely place zip ties too ;)

[Gix11]

That looks great Russ. Nice job mate.