[Closed] the URT is back

could they be made to work with new fangled shock technology?

No.

They have dug up a failed idea so their belt drive will work.
Those urts would pogo like mad when sitting, and lock up when you get out of the saddle.
You sit down when it smooth, but the sus goes mental
Stand up for the rough bits, and the sus took a tea break.
It solved a sprinting bob problem, but destroying every other design objective.... A bit like this new bike.

kimbers - Member

could they be made to work with new fangled shock technology?

No.

Think I have a Gary Fisher Joshua X frame in the shed from the late 90's if anyone wants to truly experience the sheer madness and misery of a URT bike.....actually not sure I would wish that on anyone!

When is a URT not a URT?

[url= http://singletrackworld.com/forum/topic/where-do-you-start-with-this-one ]http://singletrackworld.com/forum/topic/where-do-you-start-with-this-one[/url]

Plenty of URT based frames being ridden on the pavements around here so they must do something right 😉

Pinion need to shuffle the gearbox around a bit. The pivot needs to be concentric with the final drive to allow a belt to be used, so ideally, wouldn't be concentric with the cranks. Can't be too hard to do.

have I mentioned I've got a belt-drive full sus bike? 😉
albeit with only 1 gear...

URTs never went away did they? GT idrive....

iDrive isn't/wasn't URT.

Mike wotshisname ferrantino? did a piece about his old URT bike (Y bike iirc) was going to do a comparison about how much better bikes are now but loved riding the old URT again.

never ridden one myself, couldn't scrape together the cash for the x2 I lusted after 🙁

Guess belt drive FS will need a BB pivot a la irbandito's kona, think cove used to do one aswell.

The best way to stop people adopting the pinion is to stick it on a poorly designed frame.

I'd love to see how wide a frame would need to be to accommodate a pinion and a bb pivot

could they be made to work with new fangled shock technology?

Unless this shock technology of which you speak is new fangled enough to get a job and earn enough money to buy itself a new frame to be bolted to, I doubt it.

Plenty of URT based frames being ridden on the pavements around here so they must do something right

Yeah - they bounce up and down in the shop (and when being ridden along the road), hence making the buyers/owners think they work really well.

If the weight of the gear box and the rider is on the swing arm, does the swing arm move, or does the front triangle move in relation to the swing arm.

I don't think theres anything that terrible about a URT, its one of several ways to do suspension which comes with inherent constraints, compromises and some benefits, the majority have written it off out od hand based on shonky 90s execution of the concept, but it does have some merit for certain applications still.

But I Can't see why they didn't just produce a HT to demonstrate the use of a Pinion Gearbox and a belt drive...

There seems to be a bit of an obsession with Gearboxes only really being used in pricey Blingy FS bikes, I know theres been a couple Nicolai HTs done but it seems its always touted as a bells and whistles thing, fancy springs and a posh Gear box for Muchos ££££.

I can't see much wider adoption of the solution while its still targeted squarely at higher price point niche whores and not normal MTBers living with bugetary constraints, mounted on a URT bike or not.

Bit no one is going to say "I like this budget, sub £500 bike but what it's really missing is £1000+ of gearbox"

You can't just make things cheaper

I'd love to see how wide a frame would need to be to accommodate a pinion and a bb pivot

Alternatively, you could make a linkage system where the virtual pivot point was located at the BB. I recall that a company called Edge had a frame with such a suspension system a few years back, but they weren't very successful and didn't last more than a couple of years or so.

Good memory

[url= http://www.bikebiz.com/news/read/edge-bikes-to-go-public/04140 ]http://www.bikebiz.com/news/read/edge-bikes-to-go-public/04140[/url]

I've been thinking about something very similar for a while now.

Ir, mail me. One of the edge guys is a friend of a friend, I knew he once ran a bike co but didn't realise they did this kind of thing. I shall be trying to get hold of them forthwith.

ygm Podge

when I got into biking I always wondered why FS bikes didn't have the pivot and BB concentric. Have often penned quite an elegant solution to do it that way. One day I will build one out of carbon.

Idrive isn't a URT, it's more a sort of very complicated single pivot, with the BB hung off the bottom between the two.

if you like to sit down ALL the time then URT works.
However, if you don't and actually like riding your bike, then it fails to work when you most need it - stood up.
I persevered for a couple of years with a Mongoose with the Freedrive system which is kind of semi-URT but ultimately threw it in a skip because it was frustratingly rubbish.

Is the Maverick a similar design to the idrive?

Also if memory serves me right Pace once did a bb pivot frame but it never made it past prototype.

Some people really don't like bb pivot bikes, I however live mine

Northwind - Member
Idrive isn't a URT, it's more a sort of very complicated single pivot, with the BB hung off the bottom between the two.

I would say it's a sort of very complicated URT.
Note how the BB moves up and down with the swingarm (and therefore doesn't when you are standing on it):

when I got into biking I always wondered why FS bikes didn't have the pivot and BB concentric.

If you ride one, you'll find out why.

It's to do with Squat/Anti Squat characteristics.

glenh - Member

I would say it's a sort of very complicated URT.

Well.. OK, you can say that if you like, but it'd be wrong- it doesn't have the features that make an URT, an URT (ie, the unifiedness)

If you ride one, you'll find out why.

It's to do with Squat/Anti Squat characteristics.

Trying to remember back to my car suspension stuff and see if it relates but now my head hurts.

Are there any good books about bike suspension design like you get for cars?

PS just reminded me, did anyone from On One see my offer on the pulled thread about the cracked yellow you know what? Would be interesting to take a look if there is some doubt over crack or not.

I think the closest you'll get is a motorbike suspension design book

http://www.amazon.co.uk/Mountain-Bike-Suspension-Systems-PSYCHOLOGICAL/dp/3844330380

Found this too:

Except it contains this:

To gauge people’s preferences for suspension design, a thread was started on a well respected internet forum called BIKEMagic

oops

sit down ALL the time then URT works works.

Works better if you only do one or the other with concentric bb pivot bikes too.

First book looks interesting, as long as it's not written by a psychologist 😉

Had a quick scan through that thesis - hmm....

I'll have to dog out the Catia DVD and have a play.

Idrive isn't a URT, it's more a sort of very complicated [s]single pivot, with the BB hung off the bottom between the two[/s] way of packaging a turd.

FTFY. 😉

70 quid for that book. You can buy a bike for that

URT will never work as FS as you are not suspended from the rear wheel! The BB is attached to the rear triangle and rear wheel, therefore if you are standing on the pedals, you are in effect, standing on the rear wheel ie, not suspended. If you are sitting, then you weight is on the saddle and front triangle which is suspended.

I had an Orange X2 frame as my first FS, and it was a load of sh*te! Only bought it to get into FS, and regretted it within 1 ride (not to mention the extremely poor bearings/bushing and slack backend).

TBH I don't think its fair to slag off URT designs. At the time, they were conceived as a good idea when no-one really knew where full-suspension designs were going. Hindsight is a wonderful thing.

when I got into biking I always wondered why FS bikes didn't have the pivot and BB concentric.

Like a Kona A?

JEJames had one of those concentric linkage Edge frames hanging up in the Bramall Lane shop for ages, always wondered what happened to it once it went.

what happened to it once it went

It weighed so much it caused a China syndrome.

what happened to it once it went

I heard it was launched into space because it was causing the earth to tilt.

Did nobody notice the dirty great big picture at the start of the article??

one of the nicest looking gearbox (and indeed FS) bikes i've seen in a while.

[img] [/img]

Did nobody notice the dirty great big picture at the start of the article