Source for Closed Cell Foam – for Homemade Huck Norris

If it’s plasterzote your after it’s made by zote foams. They used to have a factory in Redhill, I used it for bike seats and I just took sheets of it out of their skip. They told me to skip dive for it when I said I wanted a bit big enough for a bike seat.

I was told plasterzote was probably suitable for seats by a nurse, I can’t remember what they used it for but the
hospital used loads of it, but it was pink.

Having felt how much the tube compresses and how little a huck norris does. I’ve taken the easy but more expensive option.

Been out for a short ride today on one of the converted wheels. Didn’t hit anything silly enough to get into any decent rim dinging situations so can’t comment on level of protection yet but what I can say is that the insert really does make a difference to the feel of the tyre.

the one I rode today was a 2.2 inch tyre with a cut down 40mm insert in it on a 19mm rim. Initially I ran it at my normal pressure and it felt a bit hard. Dropped down to my ‘you’ll be fine if you don’t  ride like a twit’ pressure and it started to feel better, but still felt a bit over inflated so I dropped it down to what would normally be ‘squirmy and vulnerable but grippy’ pressures and it felt really good.

All the extra grip of the lower pressure but didn’t feel any of the normal squirm and it didn’t feel bouncy or wallowy, I also didn’t feel a fair few roots and rocks that I would normally expect to be able to feel at that pressure so I think the reduced volume coupled with some mild insert contact under compression was working together to let me run lower pressures more safely and with some added stability.

Will get some more ride time on and try different variants but initial trial is promising and I’m now as intrigued by the changes in feel as I am by any actual rim/pinch protection they may offer. Might be worth it simply for that!

Thanks for the link. Great money-saver, hack!

For less than £5 a wheelset if you trim the 50mm in half, it’s got to be worth a shot.

Think 50mm halved in a Hope Enduro rim (23mm internal) should be spot on with 2.3/2.4 tyre? Or would a full 30/40 be better?!

Think 50mm halved in a Hope Enduro rim (23mm internal) should be spot on with 2.3/2.4 tyre? Or would a full 30/40 be better?!

I used the 50mm split in half on a 25mm internal rims with a 2.4 HR2 and 2.35 Magic Mary and it’s worked a treat. I also found that the 2m length is pretty much the perfect length for 27.5 (just had to trim the smallest amount to make some space around the valve), so if you have 29er wheels you will need longer foam or have to join extra pieces.

I rode with this set up in BPW last week, and normally when I’m there I put extra pressure in the tyres to avoid pinches and tyre burping, which I suffered with on my first visit, but this time I left them how they were and even let a bit of pressure out of both tyres after a few runs, so ended up with 15psi front and 20 rear (I normally have around 22f and 25r) and had absolutely no problems at all, and riding those rocky trails with the lower pressures was so much better. For £10 (for 2 lengths and inc delivery) it’s been fantastic VFM.

Been watching this thread with interest for a while. I’ve had a huck norris in the back tyre of my bike for a year. It’s been pretty much unnoticeable in that time but it’s clearly done it’s job. I dented a rim the other week but I didn’t notice the impact or get a flat. Upon inspection the foam strip is completely trashed – it has numerous cuts all the way around. I have installed the second strip as a replacement, but they are rather expensive for what has turned out to be a consumable item.

My next set up is going to have wider rims,  and I’ll be ordering some backer rod.

So when the tyre gets a nice big rip in it, whats the plan for those who have these huge backer rods in their tyres?

You can ride on it for a little I suspect but from what I’m seeing as it’s less dense than the likes of cushcore I wouldn’t want to ride on it for long?

I am tempted but that aspect is putting me off a little considering I’ve torn quite a few tyres recently. At least with a Huck Norris it’s easier to fold up and put in your bag while a tube is installed to get you home.

I was thinking about this the other day and a hole that won’t seal I would use the anchovies or duck tape for rips like I would normally. I also wondered whether a road/gravel tube with a long valve might work. You could then keep the foam in the wheel and the thinner tube might fit in the space above the foam?

Hope enduro rims no wonder you need a huck norris 👌😉👌

“You can ride on it for a little I suspect but from what I’m seeing as it’s less dense than the likes of cushcore I wouldn’t want to ride on it for long?”

suspect away – i punctured when i got a little lairy at the top of the larig au laoigh last monday. – saw it was a rock puncture wound in the top of the tread and didnt have high hopes of it sealing.

carried on to the bottom on a very rocky rough descent – albee it much less lairy .

tire held its shape well and didnt go all floppy  – with a full 40mm backer rod in an exo 2.4 minion DHR on dt ex5.1d

got to bottom – decided to give it a wee bit of air and see what happened while waiting on my mate and as you say didnt fancy sticking a tube in and riding back to linn of dee with the backer rod round me neck…..

mirraculously it took air , held and even did an enduro yesterday at pitfichie on the same tire !

i expect its a consumable but at 2.50 if it saves on wasting sealant , tubes and tires thats a price im willing to pay.

“You can ride on it for a little I suspect but from what I’m seeing as it’s less dense than the likes of cushcore I wouldn’t want to ride on it for long?”

With the full insert in, its like riding on a too soft tyre, even if it can’t hold any air.

Obviously you want it back to optimum asap, but as long as you nurse it, you can actually ride on it ok.

I’m sold on how the insert changes the feel of the tyre. I alluded to it on post about my first test some months ago, and completely agree with amedias.

This is looking promising, I’ve got procore in all my bikes but been less than impressed tbh…

Pro core works, and I havent punctured since, and no damage on any rims where before it was a problem for me, but both the inner and outer on every wheel need to inflated every time I ride, I’m sure the actual valves leak air slowly…. long time tubeless user, the pub bike is tubeless and hasn’t needed air topping up in over a year! So it’s an annoying hassle.

so might go down this route when my nearly new tyres need replacement.

I found procore wasn’t for me too.

tagged for future mod to the bikes 🙂

Not quite as cheap as the closed cell foam backing rod stuff, but has anyone looked at Ratbites? 18 quid per wheel, in a range of sizes. Seem reasonably priced if you don’t fancy the faff of cutting backing rod down. Very strongly considering a punt on one for my back wheel.

This is looking promising, I’ve got procore in all my bikes but been less than impressed tbh…

Pro core works, and I havent punctured since, and no damage on any rims where before it was a problem for me, but both the inner and outer on every wheel need to inflated every time I ride, I’m sure the actual valves leak air slowly…. long time tubeless user, the pub bike is tubeless and hasn’t needed air topping up in over a year! So it’s an annoying hassle.

so might go down this route when my nearly new tyres need replacement.

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Thats odd as I have Pro Core on one set of wheels that I only use for Alpine or rocky stuff and they’re fine for months.

Its not perfect though, I have punctured the inner tube both fitting it and riding. I’ve just fixed the tubes with patches, it’s rare and they deflated slowly. The Valves can be a pain for clogging too.

WTF is a ratbite?

I googled it and all I got was, uh, rat bites. It that an auto correct?

See fgf on the front page science officer, or from Google…

https://ratbite.co.uk/about

It is advised that the insert is inspected and potentially changed every 2 months.

From the rat bite home page….

sounds like longevity could be an issue?

or a sales tactic 🤔

the ratbite site doesnt inspire me to buy anything from them.

Sounds like ratbite are adding on 15 quid lazy tax to people who think it’s a faff to cut (with a bread knife if you must) once and put in a hole for a zip tie.

I saw the new Mr Wolf system at Malvern today. Full mousse insert with a small diameter inner tube to adjust feel. Looked pretty good but it’s £110. Per wheel!

OMG, that’s one flakey e-com site from the 90s!

Looks like very similar material to backer rod foam. I note their pictures seem to shy away from product detail.

£15 lazy tax could be right.

Well I’m pretty lazy, so just hit the buy button, I will report on arrival.

Looking for some for 40mm stuff for 29×2.4 tyres. Has anyone ordered 20m of it and got some left overs they’re looking rid of?

Based on this thread l ordered some 40mm and 50mm which turned up yesterday. I’m assuming its going to be like fitting a semi-inflated inner tube that’s not as pliable.

So couple of questions before I steam in trying to fit it –

1) Should it be a tight/at least snug fit in the rim

2) Lap joint with zip ties and duct tape or another way of jointing the 2 ends

3) Better to fit full circle of cut in half (semi circle)

4) Should I have just bought a cushcore or similar purpose made kit

Cheers
Carl

I cut it to butt joint and zip tied it and pulled tight till it was snug on the rim.

I went with a whole round 40mm and it has let me get back to the car without running on the rim when sealant wouldn’t work. Can’t see a half cut one doing that job.

trail rat +1.

I’ve consistently said I think it’s too low density to mirror cushcore without using its thickness to compensate.

Ok so Day1 in the alps natural stuff around let arcs with a bit of the black DH.  My rim tape let go a proper huck norris in the rear and I could ride to a point to pump back up on three occasions.  It was flat but doable.

Mate had a ratbite which looks and feels a lot like the 50mm packing rod I tried he had one moment of loss of pressure and the ratbite is looking tatty. Issues mean he’s back in with a tube but the lower density ratbite has definitely suffered more than the huck, which does show a couple of bites.

And the high-density foam is expensive.

There appear to be at least three functions this type of thing serves, and different approaches serve them to different degrees.

— pinch protection – all about placing a cushion between the area being pinched to spread the impact out and protect the rim (and tyre?) from permanent damage.  Procore and high density foam ought to do this, low density foam not so good/durable judging by the accounts above.

– changing the tyre behaviour when not pinching – Procore will do this, some reports above say low density foam does, though I struggle to see the mechanism for it, high density foam a la Huck Norris wouldn’t much, Cushcore ought to.

– keeping the tyre on the rim – anti-burping.  Procore and Cushcore ought to do this, not sure about the others.  Possibly there will be some effect with continuous low-density foam solutions as the foam gets pushed into the rim well by air pressure.  If that happens.

This is not beyond the wit of man to test under laboratory conditions if anyone could be arsed.  I would think the likes of messrs Schwalbe have done so, they seem keen on testing.

Anyone tried this with cx yet? Not cx racing but more taking your cx bike out on rides that are probably officially unsuitable for a cx bike (eg mtb trails with plenty of rocks or, come to think of it, something like the Three Peaks)

“low density foam not so good/durable judging by the accounts above.”

had mine out last week after about 700km about 200 of that in the cairngorms on the natural rocks and waterbars    a couple enduro races and at least 1 run from near the top of the larig au laoigh with a flat tire through rocks and waterbars  down to derry lodge before i was able to get it to hold air and theres no rim damage – thats the main reason i went to foam of some kind as i went from really badly dented d521s to some dt enduro rims that are renound for not only denting but workhardening and cracking when you bend em back …..  .

held the tire on the rim and kept the shape. I also burp alot less , prior to fitting this i went through a phase of burping my front tire in hard cornering even with 30psi in….. now im down to about 22-24.

took it out anyway and yes it has a couple of cuts but nothing im going to be replacing it for any time soon.

My 50mm rod in a 2.6″ rear tyre has some cuts but still looking pretty decent. I typically run 28psi, it’s a Bontrager SE4 and I’ve had no burps, pinches or flats, despite several times at BPW, a couple of Enduro races and a weekend riding in Sanremo, in between my usual riding.

Not sure about all the sciencey stuff as to how/why it works, but it definitely does have a benefit.

Vittoria getting in on the act…

https://www.vittoria.com/eu/air-liner-vittoria

I’ve got a 50mm uncut backer rod in the front and a 50mm cut in the rear (experimenting). The rear half  diameter rod was enough to hold the tyre on the bead and let me ride 2km back (carefully) to the car after tearing a knobble off the tyre and it going flat in about 10 seconds on a downhill. Getting the tyre off was a mare as the foam was holding it really tight against the bead.

When I did get the tyre off there were quite a few longitudinal cuts from the rim.

I’m convinced it’s worth continuing with the experiment, not least as I like running low pressures but don’t like dinging rims (and I’m tight!).

I am running an uncut 50mm backer rod in the front, 29mm internal rim and 2.35 Magic Mary.

Feels good, happy with the feel on the trail and it’s staying put for the Alps.

Have a Cushcore in the rear…   again happy but actually prefer the feel from the backer.

Have ran Procore for a couple of years….  needs tlc but did a good job. Couple of years back did 90,000m descent in the Alps with SG Schwalbes, Procore and Stans race….   Never a problem.

Big advocate of running some protection, just so nice to hit sections with confidence that would have had me protecting wheels/tyres before.

Being time poor and (temporarily) cash rich I bought a Ratbite insert on Monday to go in the rear after I trashed a tyre at the weekend. It arrived today, so nice and quick on the delivery as he promised.

It’s a bit more refined than backer rod foam, being profiled with radiused edges and a grove down the centre. It fits in the tyre, rather than round the rim, and I’ll give it a proper test on Sunday.

Incidentally, I rode 1.5 miles back to car on a flat tyre and it was still firmly seated in the bead.

Took the backer rod out of the back wheel.  It seems to enjoy soaking up Stans (and also Oko diluted with water 50:50).  Denser material needed.

strange mine never soaked up the sealant.

Mines not been soaking up Caffe latex.

To be fair. Stan’s didn’t seem to do all that much anyway hence why I switched.