[Closed] On One Knuckeball Carbon bar concerns - anyone got a set?

I've checked the ends of mine and have been riding them for over a year. Wouldn't worry about it.

Jim are yours different thickness too?

My enves are a wee bit varied out at the tip. I suppose, that far out it's way less stressed (you don't panic if you ding the ends a wee bit). If they're like that all teh way through that'd be bad though

Probably wrong but are the narrower thicknesses on the same place both ends? I thought one of the benefits of carbon was that you could alter the layup like that to be thicker or thinner where required to improve strength and comfort?

[quote=Northwind] If they're like that all teh way through that'd be bad though
And how could you tell without some destructive testing?

OP - if you're not happy, just send them back and get a refund. Do you really want to be riding whilst all the time worrying they are going to snap?

And how could you tell without some destructive testing?

You can ultrasound them (or even X-ray them).

I've got a hand held scanner that can check composite thickness and look for delaminations but it will struggle on the curvature of the control part of the bar.

It is entirely possible that the bar layup could change around the bar. In a similar way that you wouldnt make a plane wing the same thickness over it's length and the top and bottom skins will be different thickness too due to tensile and compressive loading (plane a bit different as it's a distributed load not end load).

I would expect thinner towards the top back direction as that is probably least likely to be heavily loaded in compression compared to the bottom, bottom front and front sections.

oh and it is entirely plausible that the inner face is a bit wavy and should you cut it an inch down it will look very different. I guess they use some sort of inflatable bag inside them so the resin distribution could be a bit off in small localised places. You can polish the ends and look under a microscope but that's not really something to do at home.

The wall thickness varies at different points at each end.

I have had two other sets of carbon bars in the past and they have both have had consistent walls.

I more than likely will send them back or wack them on the kids balance bike!

Are these the £29.99 carbon bars?

Had mine for ages. I didn't notice any issues on thickness, but that doesn't mean there weren't any. I just chucked them on and rode with them.

Had mine for a year, I'm no lightweight, theyve done uplifts, dh races, loads of enduro races, plenty of crashes, theyve held up fine, never looked at wall thickness tho!

I remember being pleased with how well made and finished mine were when I got them including the internal profile (not running lock-on grips or I'd check for you). Regardless they've been raced, jumped and crashed on 3 different bikes and the only reason I'm looking to replace them is to get a set of flat bars.

Think I'll try the RSPs egos as I'm plenty sold on good value carbon bars.

Perhaps it is a "feature", similar to Easton taperwall.

Bought a set of these last winter for my Fatty and been happy with them ever since. Can't say I inspected them that closely, just fitted and rode. They have been fine for all my riding so far.

I would guess they are produced using a bladder core in a profiled mould.

Irregular ends might well be caused by the bladder having a seam/join of some kind or not sitting quite centrally?

They probably have sufficient fibre density/distribution, but the resin distribution is obviously a little variable, odd as it might sound the thinner bits are likely to be a wee bit stronger as they're better consolidated...

Consistent wall thickness and fibre density closer to the centre of the bars where there's more stress is the main concern, unfortunately it's harder to verify that non-destructively...

You bought a cheap bit of kit form On One and are now querying the quality of said item..?

scotroutes - Member

And how could you tell without some destructive testing?

I'd loan the bike to my brother and get him to do some big drops

I think we need you to cut through them at say, 20 mm intervals to see if this defect runs through!

That's assuming you've shone a torch in the ends and had a look for this seam running up inside the bar rather than just assuming it does because it's there at both ends.

If you ever wreck your Bronson, Cut some sections out of the frame....might be a bit like the Knuckeball!

Mine are like that, it's just how a lot of carbon layups are, it's very difficult to get smooth surfaces inside and out and i guess they're consolidated with a bladder made from tubing, so at the end you'll always get wrinkles as the diameters much smaller than the bladder.

What process are other manufacturers using that results in an even end profile?

Laying up on a mandrell that isn't removed untill the resin is cured? Shaped bladders? A thin insert/shim in the end?More than one way to skin a cat. Some frame manufacturers claim to get the internal surfaces of frames smooth, others dont, i suspect a lot look like that or worse inside.

Smooth is probaby (undoubtedly) better, but the On One bars will just be a bit overbuilt to compensate.

the inside of LB rims is pretty wild like that too if it's any consolation.

Smooth is probaby (undoubtedly) better, but the On One bars will just be a bit overbuilt to compensate.

I didn't notice the inside profile being anywhere near as wild on the Knuckleball bars I put on the Mrs'bike. Of course I'll have to go check now.

Send the tat back. It will bother every ride until they snap and kill you dead.
I wouldn't be surprised by some slight variation in thickness from the various layers overlapping etc. but I wouldn't be happy if they went from 1mm to 3mm unless it was designed and built like that by a reputable company.
I have a set of raceface sixC with no grips on that i just checked and the id- and od are a very even thickness all the way round. Same as 2 old Easton carbon monkey bars I have in the garage.
I really would send them back.

Thanks for the responses, much appreciated.

Think I will stick with the Alu Renthals!