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Onza Proto - With The Dropped Chainstays, In Nottingham


Dan6061

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Onzaboymark had it for a while...

Then Onza decided to scrap the dropped 'stays idea due to clearance in comp's or something?

Was basically for a new chain tension idea (where a bolt pushes the axle/wheel back, and so you don't have to split the chain...

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Mark had one for a while, supercycles was/is based in notts too so i guess theres a strong possibility that they let someone around there ride one and he was just out for a quick session. If its not on the site/sites though i'd be inclined to say its just another proto model being used and not a production one.

P.s. Sorry i didn't text back earlier mate, lazyness got the better of me. Looking to start your picture tomorrow ;)

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Onza are a British company operating from Nottingham and we have an ongoing and vigorous R and D programme. The dropstay frame is one of many concepts that we have developed and it is ongoing. Just because things go quiet it does not mean we have dropped it. There are several dropstay frames around including a 26" version and they are constantly under review. We have even worked with a belt drive supplier on the same frame as the design lends itself to that usage. We have high hopes that the design will find its way into production in 2008 but before we do so it will have to have proven benefits.

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Onza are a British company operating from Nottingham and we have an ongoing and vigorous R and D programme. The dropstay frame is one of many concepts that we have developed and it is ongoing. Just because things go quiet it does not mean we have dropped it. There are several dropstay frames around including a 26" version and they are constantly under review. We have even worked with a belt drive supplier on the same frame as the design lends itself to that usage. We have high hopes that the design will find its way into production in 2008 but before we do so it will have to have proven benefits.

I so want to work at Onza, I'd love to be coming up with new designs all the time.

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dont stretch that easy either.

Gearing will be abit difficult though id imagine.

A toothed V belt would work a treat.

no more so than a vehicle cam belt. which doesnt stretch at all really(maybe a few mm with time, but then tensioners take this up)

wouldnt really see gearing being an issue. could do it one of two ways(that i can think of right now)

1) different sized belts, bearing in mind that the frames are going to be specifically made for it i should imagine, as are the rear hub pulley and front crank pulley(seems so odd saying crank pulley in a biking term) then theres only going to be need to have say 3 lengths of belt and 3 different rear pulleys. (say 1.29:1, 1.125:1, and 1:1)

or one belt size,and youd buy front and rear pulleys as a set to match. (i.e a 50mm diameter rear pulley : 64 mm diameter front pulley, a 54: 60 pulley set, and a 57:57 pulley set) the length between the pulley centres never changes on a rigid frame(think bb and hub centre) and the total circumfrence of the two pulleys together never change.

could work rather well actually, would expect to see a helical tooth belt though, due to the greater load transfer capacities of one(greater surface area of the teeth) and the fact that it self aligns.

other than the freewheel wear, which could be horrendous if the belt was overtightened. and the resistance of turning the belt. most of the other point a are a plus point.

wear on the pulleys/belt would be no where near as bad as chain wear/chainring wear. ( a camshaft pulley will turn something like 350 million times in the average life of a timing belt (often much higher, thats calculated on a 60,000 mile belt on a petrol engine), and you never hear of the surface/face of the pulley being the cause of cambelt failiure, and quite often their skipped on timing belt changes too so will often do double that)

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One BIG property of belt drive systems is the fact that there's a limiting maximum power/torque that you can apply.

If a decent solution to this can be found, then maybe it could possibly be looked into in more depth

Would be interesting if it could be applied in this sort of situation. Chain tension would be a peice of piss!

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Nice, belt drive,! Is this just on paper or has it been put into practice? I really do like that onza seam to be exploring further into trials "teck". This is good for trials, trials seams to be getting more popular, and the bikes better/lighter. I'd love to see any picks of any belt drives as i am quite curious as to how they would look, belt drives are strong, so with a little fiddling with the molecular, properties of the polymers that are used then the belts will be uber strong and light!, and gearing will be fine for mods anyhow.

Pro's so far, much lighter!/strong/cheaper?/functionality/usability

Con's new drive system to be made, will have to be universal to other, freewheels, and hubs/ would have to make hub + freewheel modifications that could be sold to consumers so they could change from existing drives to the new onza one.

Good area to explore! + 1 to onza DEVELOPE, maybe we will all use the belt drive in years to come? I would use one,,,,,,,, do it before deng do!

Maximus!

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The positives are great, The belt weighs 40 grams, (Kool chain weighs 400 grams) Does not stretch nor snap (get a cam belt out of a car and try to brake it), We have had it working on the very bike that started this topic (cant find a pick though Doh!) We have had issues with it snapping in tests due the "chain/belt line" not being straight. We may nail it one day, We may convert you all, We might just get tired and have a nap.

Ill up date you guys when we have a little progress.

P.s good thinking on how the gears would work, Was just single speed market we were aiming at though.

adios!

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Does not stretch nor snap

We have had issues with it snapping in tests

Something there doesn't quite add up! :P

If a belt an go in an engine, it'll go on a trials bike.

get a cam belt out of a car and try to brake it
Get a chain and try and snap it

Obviously there's going to be pros and cons, it's all about summing them up/doing what you can to make it work as best you can. If you find a way to make it work, and work well enough to be deemed better than, or at least as good as, the current chain drive setups, fair play to you!

Would be a really interesting project to work on, I'd love to do something like that but my course at uni doesn't really allow for it there, and I don't have the means nor money to try it properly myself :(

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For any one who may not have realised it, the reason we used the drop stay frame for the belt drive, was because you cannot split a belt like a chain. The drop stay allows removal of the belt/chain without splitting, so this frame was the only one suitable, and was one of the reasons why the frame was evolved in the first place.

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Wider BB shells like on some DH bikes (& Varios)? Would give better tyre clearance and still allow for short chain stays.

We made a T-Lite a couple of years ago with an 85mm shell. Test results wre inconclusive ie. pro's and cons.

Could you not make a frame with some sort or removable chainstay? My specialized dh bike back end came in about 4 pieces so strength shouldn't be an issue.

I am sure your downhill frame has the luxury of suspension to soften the knocks. Fixed joints are a problem enough on Trials bikes without having to factor in removable sections.

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Onzaboymark had it for a while...

Then Onza decided to scrap the dropped 'stays idea due to clearance in comp's or something?

Was basically for a new chain tension idea (where a bolt pushes the axle/wheel back, and so you don't have to split the chain...

Still got it, actually! It didn't make the trip to London 'cos someone mullered it and it needed a load of work doing to it, work I couldn't do on the budget I had then. All the bits are bought now though, so hopefully if I get the time this winter I'll be able to resurrect it.

It was a super nice frame, and I was always a bit disappointed it didn't make it into production back then. The geometry on it was spot on, and the feeling of stiffness from the frame was amazing. You don't even have to just take my word for it - I whored my bike out to various people who were all really into it, not to mention Ben Slinger winning the Euros (Or Worlds?) on it prior to me receiving it.

Belt-drive could be really interesting. I don't think the "falling to bash onto it" thing would be much of an issue, certainly no more than if you happened to catch your chain and mashed the top of the links a bit? Either way, I hope to see how it all works out, could be pretty revolutionary!

We made a T-Lite a couple of years ago with an 85mm shell. Test results wre inconclusive ie. pro's and cons.

Did you guys also make one with a 105mm BB or something ridiculous like that? I remember seeing the 85mm one up in Nottingham, but thought there was a mega-wide one too...

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That belt drive thing seems funky, good luck develop it.

That "belt bash" some of you guys were talking about won't be possible if the frame looks anything like this?

http://www.onza.com/bikes/mod/protomod/Onz...ypeMod_bike.jpg

You will just hit the frame or the bashguards

or ?

Edited by Aleksander
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That belt drive thing seems funky, good luck develop it.

That "belt bash" some of you guys were talking about won't be possible if the frame looks anything like this?

http://www.onza.com/bikes/mod/protomod/Onz...ypeMod_bike.jpg

You will just hit the frame or the bashguards

or ?

I LOVE THAT BIKE :o

AND I SOOOOOOO WANT ONE

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