WheelchairDriver

Tyres are not exact. Sizing is nominally stated. So some 3.50 tyres may be wider, or taller than the measurement suggests for eg. But this is usually slight.

Also rim width, and pressures change these measurements and shapes of tyres too.

A 4.80 wide tyre really needs a 3.75 to 4.25 inch wide rim, as its almost 5 inches wide.

https://allterraintyres.co.uk/index.php ... =page&id=8

Useful if you dont know what all these types of markings mean.

Buregerman is quite right that marked tire sizes are only nominal. For example, the Carlisle 4.80-8 Turf Saver tires on Rachi's chair show the following in the catalog: Running at 5 psi, however, there's about 1" of squish.

Nice but 1/2 too wide for my tyres...

Also worth noting that you only want to count 1/2 the difference in nominal diameters when figuring the change in chair ride height...

After all, only half the difference is on the ground, the rest is at the top of the wheel, waving around in space....

I.e. tire size 3.00 x 8 = 3 + 3 + 8 =14" nominal OD, but if measuring RADIUS, we get 7" nominal between the axle and the ground...

Going up to 3.50 x 8 = 3.5 + 3.5 + 8 = 15" nominal, but the radius is only 7.5" so you only get a half inch chair height change.... The total might be a concern for fender or other clearances, but even then you are usually only worried about half the difference in nominal OD...\

ex-Gooserider

Hi all

Posting a link I found. have searched threw site first but not seen it.

https://www.sip-scootershop.com/en/prod ... +_30701010

Mind The Gap wrote:Hi all

Posting a link I found. have searched threw site first but not seen it.

https://www.sip-scootershop.com/en/prod ... +_30701010

$114.00 per tire?

Apologies got side tracked, link for tyres only. https://www.sip-scootershop.com/en/prod ... +_80204003
In this link scroll down and watch video, https://www.sip-scootershop.com/en/prod ... +_30701010
was wondering if rims would fit on chair somehow.

Cheers Paul

You could. But the ones shirleyy shows above are also tubeless tyres/rims and so far superior to tubed tyres. In fact all my chairs are tubeless tyres and rims. I dont like spine jarring solid, puncture free tyres, and also dont like punctures. Tubeless beats them all hands down.

Burgerman wrote:You could. But the ones shirleyy shows above are also tubeless tyres/rims and so far superior to tubed tyres. In fact all my chairs are tubeless tyres and rims. I dont like spine jarring solid, puncture free tyres, and also dont like punctures. Tubeless beats them all hands down.

I thought you still used tubes in your front tires, right?

Correct, but these are rear tyres, 3.00 and 3.50 x 8 rim.
Or 120/70 - 8 on the salsa, 130/60-10 on the BM2 green chair, and 6.00 x 6 on the BM2/BM3 black chairs.

Fantastic, thanks for the help in purchasing this stuff, and shipping so quickly...

I will look forward to getting the package...

ex-Gooserider

Heygnow wrote:Not wanting to sound dumb but............

What are the drawbacks with tube tires?

How about tyre rotating on the rim? That would eventually rip the valve stem right off. Have the remount the tyres every so often which seems to make it necessary more and more frequently. A case of making it worse by fixing it.

Happens in bicycles. That may be one reason cars no longer use tubes. (I forgot all the reasons tubes were bad.)

Biggest issue with tubes is that they are like a balloon. Pop... And if they are punctured with say a nail, the tube expands around the hole/nail and releases the air. In a tubeless tyre, you can have a nail in for a week, and no deflation as it blocks the hole. The tube is bonded to the tyre carcase, it cant expand. When the nail is removed the hole seals itself auttomatically unless its a very large hole. And then it almost does. So adding a little tyre sealer prevents you ever getting a deflation even if punctured. But this stuff almost always fails to work in a tube tyre. This is why cars, trucks, aircraft, motorcycles, and even some push bikes all use tubeless tyres MASSIVELY more reliable. You get home!!!

Not sure who you were asking this? If me, I have been working more on the supply than the wheels, but I did look them over pretty carefully.

No signs of damage, and most of the finish was pretty good... From any sort of distance they look great....

If I wanted to be really picky, I could get annoyed that the edges on some of the holes weren't as well deburred as they could be, and the surface finish on the insides of the holes is a bit gnarly... I haven't tried measuring precisely (and don't plan to) but either the outside holes aren't all the exact same size, or the hole pattern isn't totally round and centered, as the distance between the curve where the center flange joints the rim and the edge of the holes varies a little... The most noticeable difference is the relative position of the valve stem compared to the holes... On two of the wheels, the stem is pretty much centered between the outer holes, on the other two, it is noticeably off to one side....

Ironically, I actually would have liked it better if the stem were in line with one of the holes... There is a big offset in the flange depth between the two sides of the wheel, and I suspect it would be easier to adapt if you could put the deep side to the inside (would move the tire in more) but that's the side the valve is on... There was some discussion about drilling a new valve hole to mount the stem on the narrow side, but I don't think there would be enough room... If the valve was in line with one of the holes, it looks like it would have been possible to spin it around 180* so it stuck through the hole to the narrow side.... (the surface finish is good enough that I'd have no worries about mounting with either side out...)

ex-Gooserider

shirley_hkg wrote:

shirley_hkg wrote: Tyre & rim look pretty nice , at 1/5 the cost .


Have you checked if wheels were damaged ?

I did just start looking at the caster wheels I got from Shirley, and am seeing a LOT of issues...

The wheel itself looks nice, gold cad? plate steel, but the bearings are mounted in the center hub with no spacer in the middle (bad for ball bearings like these that get side loads when turning...)

The bearings themselves are steel 6202Z - metal shielded rather than rubber, which isn't a big deal...

Another annoyance is that 3 out of the 4 bolts on the one caster I've taken apart so far were over-torqued to the point of thread damage, about 1/2 turn from being stripped.... As far as I'm concerned, that means needing to replace them...

I also notice that the bearings are not inserted to a uniform depth, or apparently against the ridge inside the hub... The first wheel showed depths from the edge of the hub to the bearing 0.084" / 2.15mm and 0.161" / 4.10mm. The second wheel had depths of 0.107" / 2.72mm and 0.168" / 4.27mm... I tried pressing the bearings in further with a bolt and some flat washers, got a good bit of movement - and now show 0.170" / 4.33mm on both sides.... Poor QA on assembly, but fixable...

However what is a significant issue, is that the hubs are longer than the forks are wide... My caliper says the hub is 3.060" / 77.68mm wide, while the fork is only about 2.965" / 75.33mm between the legs....

I also subtract points for not cleaning the welding splatter off the flange before plating it...

Unlike the rear wheels or the power supply, these seem like rather a poor quality item overall... I can make them work I'm sure (as BM says, it's just metal...) but it will take a good bit of work...

Shirley, I believe these were supposed to be the same wheels you used on your chair? If so, how did you adapt them?

Did they fit inside your forks without being cut down? Or did you cut them down or spread the forks? (they seem like a heavy casting that would be hard to spread...)

I also noticed the end of the valve stem sticks out past the rim - does it clear the fork?

Unless there are other suggestions - it looks like what I will need to do is:

1. Get a better set of measurements on how centered the hubs are in the wheel and take a total of about 3mm off the ends, keeping the wheel centered in the fork.

2. Make a center spacer - presumably around 0.75" / 19mm OD, with a 15mm step down on each end, and a 7/16" bore (the stock axle diameter) and put it in while replacing the bearings.

3. Make end spacers to fill the gap between the bearings and the outside of the forks - I'll probably try to make something that is a fairly close fit to the recess in the hub just to try and minimize the 'furball' buildup... So about 34mm OD, with a narrow 15mm step on the inside and a 7/16" bore...

Do you think aluminum would be OK, or would I need to try doing stainless?

Shirley, does the place you got the caster wheels from have any dimension drawings by any chance? I can do my own measurements (and probably will regardless) but having manufacturer specs would be good as a double check...

ex-Gooserider