DIY Ghetto Tyre Inserts

[dlovett]

Hey, those of you that have made your own inserts, can you suggest a good uk supplier for the foam and also any suggestions on what diameter for 650x47 and 29x2.6.

Would these be any good?

https://www.dortechdirect.co.uk/sjg-pol ... cular.html

TIA

[Jurassic]

That's what I used (and bought from that company). I ended up buying 19m of the stuff because it was (relatively speaking) so cheap (I've given loads away to friends to try). I've found that one length is perfect for 27.5 but I've had to splice a bit extra on to make it long enough for 29. The tyres that I've used it with have all been in the 2.4-2.6 bracket and I've managed to get the full section of rod into the tyre with a bit of effort (some of the threads on STW that inspired me to try it recommended cutting the rod in half along it's length to fit it in). I'm still using it in the rear tyre of both my enduro bike and ebike (which is also a big hit bike) in preference to commercially available options but prefer to run insert free up front. It gives a genuine run flat capability and I've switched back to using it after running "proper" inserts for a while as I think that it works better.

[dlovett]

Thanks for that info very helpful. What diameters did you use in the various wheel sizes you mentioned?

Thanks

[Jurassic]

Thanks for that info very helpful. What diameters did you use in the various wheel sizes you mentioned?

Thanks

I just bought one batch of 40mm diameter backer rod but you may want to try a smaller diameter if you plan to run narrower tyres. 40mm fitted into my 2.4/2.5 WT Maxxis tyres and 2.6 WTB Rangers.
For different wheel circumferences I had to add a bit extra to make it long enough to work with 29er wheels but 27.5 was fine with just a single length. To add a bit (or join the two ends to form a circular insert) just use cable ties to stitch the sections together. It looks a bit messy but once it's inside the tyre you can't tell where the joins are. I also added some extra sealant to offset the fact that you effectively lose a bit with the various surfaces of the insert (although the backer rod is closed cell foam so shouldn't actually absorb much). I try to position the join in the backer rod at the valve to allow the air to get in but I have had the inserts creep inside the tyre which effectively blocks the valve (I've had this happen with pucka inserts as well though). With the backer rod I just removed the valve core and stabbed the backer rod with a pick to release the air.

[rudedog]

What is the benefit of this?

[dlovett]

What is the benefit of this?

I had the first puncture in years that sealent didn’t sort, so I want to add some run flat to my tyres just in case.

[Jurassic]

What is the benefit of this?

Run flat as dlovett says but also bomber protection for your rim and the ability to run low tyre pressures for more grip. Tbh I don't use inserts on my bikepacking bike just in my long travel trail/enduro bikes. The benefits would be the same for bikepacking but in the event of a catastrophic tyre failure in the middle of nowhere that necessitated putting a tube in you'd have to factor in what you were going to do with the insert (leave it in the middle of nowhere as litter or deal with carrying a big length of foam covered in messy sealant). That fact has put me off using inserts for bikepacking, YMMV.

[boxelder]

I nearly bought some for a tour in the Alps but the shop selling them pointed out this:

factor in what you were going to do with the insert (leave it in the middle of nowhere as litter or deal with carrying a big length of foam covered in messy sealant). That fact has put me off using inserts for bikepacking,

[fatbikephil]

Don't the inserts keep the beads in place so you can set the tyre back up tubeless with a hand pump after patching the tyre? Pete, who I was riding with quite a bit on the Highland Trail, managed this after a spectacular puncture - plugs didn't work so he bunged in a tube - when it let go he bunged in a second tube, when it let go he patched the tyre, re-seated it (thanks to the insert) and managed to carry on for another 75 miles before sourcing a new tyre.

[Jurassic]

Don't the inserts keep the beads in place so you can set the tyre back up tubeless with a hand pump after patching the tyre? Pete, who I was riding with quite a bit on the Highland Trail, managed this after a spectacular puncture - plugs didn't work so he bunged in a tube - when it let go he bunged in a second tube, when it let go he patched the tyre, re-seated it (thanks to the insert) and managed to carry on for another 75 miles before sourcing a new tyre.

I suppose anything is possible if you're determined and resourceful enough.

[fatbikephil]

I suspect 'desperate enough' is nearer to the mark....

[dlovett]

I've just ordered 5m of the 30mm. 2m for the 650x47 Ventures and 3m for the 29x??? The 650b is needed more urgently as I haven't got the 29 tyres of choice yet.

I was going to get 40mm for the 29, but the postage increased by £16 as soon as I put the 40mm in the cart. If 30mm is too small, then I have a spare set for the 650b's.

[Jurassic]

I just fitted a new rear tyre to my eeb today (Maxxis DHR 2.4) and had to remove the old tyre and fit the new one with the backer rod insert in place.
It is a bit fiddly but it's fine once you've broken the seal at the bead getting the old tyre off. Refitting, you need to work the insert into the right place inside the tyre by manipulating it. Again it's not really hard, just a bit of a knack. If it seems impossible at first, don't give up, just think about what you're trying to achieve and where the insert needs to be to do that. Like all tyre fitting things, it's all about technique not brute strength.

[dlovett]

Will keep you all posted. The ventures have been very easy to fit and seal, needs a lot of force to break the bead to remove, but it’s doable. Hopefully they will arrive before next week’s Audax, which will be a good test of them on.