Bike tyre air nozzle

When fitting tubeless bike tyres it is usually necessary to have a fast blast of air to get the beads to seal enough to hold air then more to seat the beads in the rim. This is easiest done with a compressor.

Most tyre inflators, for compressors, use a rubber hose with a Schrader, car, valve end. In to which a small Presta valve adapter has to be fitted. That combination can be difficult to hold in place on a Presta valve while also trying to hold the wheel when it is not on the bike. 

I have designed an adapter that fits an air blower tool, which can be easily held on a Presta valve with or without the valve core installed.

An early version

It took a few attempts to get it right. The first version only fitted when the valve core was removed. It worked and didn't need a washer but it is more convenient to be able to use the same tool to complete the inflation, so I designed some more.

Disappointing adapter

Another attempt used a standard Presta valve adapter. This was disappointing. It was hard to hold in place and, as is typical with these adapters, the rubber O-ring kept being pulled off when removing the tool.

The latest design uses a rubber O-ring that fits tightly in a deep groove.

The metric O-ring has a 5mm internal diameter with a 2mm cross section, making it a 9mm outside diameter. It is a snug fit and needs something like a blunt needle or small nail to help get it in.

It is designed to 3D prints without any supports. I used 2mm thick walls and a 30% fill. My preferred filament is ColorFabb nGen.

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Download 3D models:
Tyre Air Nozzle, STEP and STL (Zip)
Licence attribution - small business exception

My models in the GrabCAD library.

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Bike build - Part 5

Tyres

I'm not sure putting tyres on the wheels really counts as being part of the bike build but as it is essential, I thought I'd include it.

I've selected the same tyres and wheels that we have on other bikes and I have some tips, in another article, about fitting them.

All our mountain bike tyres are setup as tubeless.

The Schwalbe, Hans Dampf, tyres need a lot of effort to get them on the rim.

I like Hope Fortus wheels. Their Pro 4 hub just feels and moves as a quality component should. The 26mm rim size suits the 2.35" width tyres that I like to run.

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Bike build - Next instalment

Bike build - Previous instalment

Bike build - Part 1

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Lessons learnt fitting bike tyres

I don't have to fit bike tyres very often so I am not an expert. Each time I do, I have to remember what I did last time. Years apart for some tasks!

This time I was fitting some 29" Schwalbe Hans Dampf Supergravity tyres to a couple of different rims. Fitting them did not go to plan, so I have learnt a few things:

1. Tyre leavers are for getting tyres off not usually for putting on
I've fitted other makes of tyre and was able to force the tyre on the rim with just a bit of effort. The Schwalbe's, I've just fitted, were more difficult.
One side goes on reasonably easily, with a bit of effort, but despite positioning in the hollow, as best I could, I just could not get the other tyre bead over the lip. I resorted to tyre levers but they just scratched the rim and I felt like it was only going to work if I had three hands.

The solution I eventually worked out was that if I manoeuvred the rim to the corner of my bench and forced down on the tyre I was able to get it most of the way on. I then just needed to use a single plastic tyre lever, in the centre of the remaining short length, while pulling the tyre down with the other hand to hold it on the wheel. The single tyre lever in the middle was then enough to  flip it over the edge. Still tough but worked.

I have since managed to fit them without the tyre lever. Which is how I would expect to fit tyres. [Update: I have decided that it depends on the weather. In the warmer months tyres are easier to fit!] To fit the troublesome tyres, I had to get it setup just right, to be able to put pressure using both hands to pull the whole tyre down so the bead popped over.

[Update: I now use bead sealant. Brush that on before fitting and it is much easier to slip the bead over the rim] 

I bought the Supergravity variant of the Schwalbe, Hans Dampf, tyre because it has the toughest sidewalls. I guess that has a disadvantage when trying to fit them!

2. Put the tubeless tyre sealant in AFTER the tyre has been fitted
It was a lot harder struggling to get the Supergravity tyres on the rims whilst also trying to prevent all the sealant pouring out.
I gave up on that idea, emptied out the sealant before fitting the tyre.

Once fitted and inflated to pop the bead on, I used a large syringe to inject the sealant through the valve tube.

This also has the advantage that it is possible to check that the tyres hold pressure without the sealant masking poorly fitted tyres. If I have time I like to leave the tyre inflated for an hour or so, without sealant, to see how well it holds pressure.

The tyre sealant, in my opinion, is primarily for punctures although, in most cases, it is necessary to help the tyre stay inflated for longer.

3. It's better to replace rather than repair tubeless rim tape
Changing the tyre was the result of a 3" nail. It also punctured the rim tape through to a spoke nipple and nearly punched a hole in the inner trough. I thought it would be simple enough to patch a section of rim tape over the existing. After one ride the tyre had deflated!
Very disappointing. After the struggle to get the tyre on the wheel, I had to do it all again. This time I stripped off the old rim tape. It came off very easily, so I should have done that the first time.
This time, with a completely fresh install of rim tape, the tyre has stayed fully inflated.

4. The tubeless rim tape needs to stick, a little
I used Stans No Tires Tubeless Rim Tape on the first wheel I did. That stuck well. I did exactly the same from, the same roll, on another rim and it would not stick at all, even after carefully cleaning with isopropyl alcohol. I'm guessing it's something about the material used to coat the inside surface of the rim.

On my first few attempts with this wheel, I managed to keep it down just enough to get the run round the rim. I then fitted the tyres and inflated them. As the tape was a seal from bead to bead, it inflated. It lasted a few rides but after a while it would deflate overnight, despite the sealant.

I've now had another rim which was similarly difficult to stick to and would leak air through a spoke nipple. I eventually had to sand down the inside of that particular rim. It was the only way to get the rim tape to stick at all. I have found that for a long term seal, the tape has to stick round each spoke hole in the rim.

I think the rim tape, being the correct width for the tyre, minimises leakage and in many cases, I have found, that is all that is needed, stick or not. The typical recommendation of about 1mm or better 2mm greater than the internal width of the rim, works best for most wheels that I have worked on.

As a result of the troublesome wheels, I have tried lots of different rim tape. They all work to some degree but my favourite, because it conforms fairly easily to the inside shape, is from Muc-Off. [Edit: I have been told, using a good hair dryer or carefully with a lower power heat gun, that other tape can be made to conform.]

By writing these notes down, hopefully I will remember them for next time.

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Fitting a tubeless bike tyre

As mention in a previous post, the hub on my bike made a grinding noise and the freewheel had a large angle between teeth. For those reasons I have changed the back wheel.

I am a fan of tubeless tyres. Mainly, I like being able to ride without having to stop for punctures.

First job was to fit the tube tape to the rim. The tape supplied with the Hope wheel was a thin plastic which was fairly stiff. I found this a bit of an odd choice because it has to curve in both directions and this tape didn't want to do that.

I fitted it as best I could, working round the wheel to get as many of the bubbles out as possible. Mainly I made sure I had sealed round every spoke hole. I used a cloth to keep going round the rim and attempt to bend the tape to the shape of the rim.

The result was not as tidy as I was expecting to be able to achieve but eventually had to accept I wasn't going to get it any better.

I cut out the hole for the valve and tidied up the edges, as best I could.

I tried to get the tyre off the previous wheel without loosing too much Stan's Tire Sealant. The tyre was easy to get off with a couple of tyre levers. I lost about half of the tyre sealant, transferring the tyre to the new wheel. It made a mess on the workbench so I ended up putting a wadge of paper towel under the tyre to soak up what came out.

I had watched the Stan's video on how to fit tubeless tyres and was following their suggestions for the most part.

I got most of the tyre bead inside the wheel rim but before closing the last bit, I sloshed in a fair quantity of Stan's No Tire, Tire Sealant, to the bottom of the tube. I'd guess, over 100ml (about 4 oz).

I used two tyre levers to get the last bit of the tube lip inside the wheel rim. I lost a bit of sealant doing that but not too much. I rotated the wheel a couple of times to spread the sealant about.

From what I have read, getting the bead to seat is the bit that people have trouble with. I have a full size car air compressor, which makes that job fairly trivial.

I have modified an air blower, with a thin nozzle and a rubber grommet. I set the air compressor to near it's maximum 90 psi (6 bar).

I inflated the tyre without the valve core in, so that I could inflate it as quickly as possible. To my mind this helps to get the beads to seal on the edges of the rim, which helps to inflate the tyre.

I rapidly inflated the tyre to it's maximum 60 psi (4 bar) and checked round both sides to see if there was any sign of leaking. My own tip is to let the tyre deflate and see where the rim comes away from the bead and inflate the tyre again until I am sure the bead has seated. I pulled on the side walls at any point that did not look completely even.

I was pleased that my poor looking rim tape was sufficiently sealed to hold the air in.

As I had done this without a valve core, the tyre deflated when I released the air blower. As that was obviously going to happen, I made sure that the tyre was not pulled off the rim, by laying it horizontal.

I fitted the valve core and inflated it again. This time finishing off with my normal track pump which is easier to fine tune the pressure.

I left it for a while, over pressure, at 3 bar (about 40 psi) to make sure the tyre was holding air and then once I'd finished fitting the brake disc and cassette, I dropped it down to about 2 bar (about 30 psi).

Once on the bike, the gear change had to be adjusted. The cassette probably sat no more than a millimetre different to the previous but that made it necessary to redo all the setup.

The following morning and the tyre is still fully inflated.
:-)

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Tubeless bicycle puncture repairs

If there is any advert for using tubeless tyres, it is how easy they are to repair a puncture.

Firstly, I would thoroughly recommend using the goop they put in them to seal small punctures automatically.

Shelley has Stan's No Tubes Tire Sealant in hers. On our ride today we heard a loud hissing and could see the white sealant spraying out. All it took was to rotate the tyre so that gravity brought the sealant down to the hole and the hissing stopped.

Tips: Each tyre needs between about 90ml to 120ml (3oz to 4oz) of Stan's Tire Sealant. That's one and half to two of the small, 2oz (59ml), bottles. I just put two bottles in each tyre and spin the wheel a few times. I've successfully used it to repair a puncture in an inner tube. That only needed one bottle. The tube was still in the tyre on the bike. Quick and easy, get you going fix.

We didn't even have to add any more air. Shelley rode the, nearly, 10 miles home without any ill effects of the puncture.

Since then, I've tried to add some more air and the extra pressure has burst the seal where the puncture is.

That was easily fixed with some tyre repair strips.

It was very easy to use the tool to insert the tiny 'anchovy' style strip in to the hole. About two thirds in and one third out. That can then be cut down, leaving about 3mm protruding.

The puncture was sealed immediately and I was able to pump it up to a much higher pressure than needed.

I thoroughly recommend carrying this type of repair kit. The Genuine Innovations kit, I have, uses butyl rubber rope strips. Sometimes called 'anchovies', sometimes called 'strips of bacon'. That are sticky and inserted in to the tyre as they are without messing about with anything else. There is a refill kit available.

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Smarter wheels

Today the refurbished alloy wheels arrived and were fitted with new Goodyear Wrangler DuraTrac tyres.

The wheels were from eBay and I had them refurbished by Tyre-Smart in Witham, Essex. They send them to a company, I think they said they are in Kent, which specialises in refurbishing wheels.

They have done a fantastic job, I am very pleased.

I deliberately wanted to stick to genuine Land Rover wheels. There are plenty of other alloys but I did not know if they had been designed with off-road abuse in mind. I thought it better to stick to genuine Land Rover wheels.

I used copies of old brochures to make sure that what was for sale on eBay was genuine Land Rover. There are some very close looking that were not Land Rover options. There are also plenty of already refurbished Land Rover wheels but they were more costly than having my own done.

The 63mm black centre caps are easily available from eBay.

It took me ages to select the tyres I wanted. From past experience, I know I am unlikely to swap the wheels round just to go off-road, or more commonly, not swap back for on-road use. I was therefore after a set of all-terrains that I could drive on all the time but as chunky as I could find to give me the best chance of traction in the mud off-road.

By chunky I mean that they have wide tread spacing and, for me, most importantly a more square profile, viewed front on. The idea is, that gives better side wall grip to pull out of muddy ruts. That's just my thinking, apart from my own experience, I have no evidence of this being better.

I like B F Goodrich All-Terrains but they are not available in a size suitable for a Discovery 4 without changing the rolling circumference. I wanted a standard overall size. Partly so the odometer reading remains correct but also to avoid insurance complications.

Eventually I found the Goodyear Wrangler DuraTrac in 255/55R19 111Q.
The Goodyear web site is hopeless, it does not show any of the tyre sizes, I nearly didn't look at them but the tyre dealers had more information and there were a few good reviews by other Land Rover people.

The DuraTrac tyres are exactly what I was after. I've driven them for about 70 miles, so far. Nearly all on-road, except for a dry grass car park, and I am very pleased with them. I can't notice any road noise, if there is any, its definitely not intrusive. Not that I worry about that, I drove the D2 on mud-terrains for a year.

I've also replaced the spare wheel and tyre. I like all my tyres and wheels to match so I can swap them round.

I am not keen on space saver spares, so that had to go.

I've fitted the spare with a security plate to reduce the chance of it being stolen.

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