Clincher tyre tubes and pressures

[Steve Slocombe]

To answer an earlier post I run my VL drop centre tyres at 28-30 psi despite the handbook advice. I think the sidewall material on earlier tyres might be stiffer than today, so maybe that is partly why they could run them at lower pressures. Plus of course most riders today weigh over 150 pounds.

[Bbowers882001]

Just joining the thread and may be 'late-to-the-fight' and I will also add I'm not the sharpest knife in the drawer on this. I've struggled to keep my JD clinchers inflated. I finally figured out.....the 'armor all' tire dressing was causing the tires to slip on the rims....duh-uh. Since the front wheel is 'sans brake' on the 1925, Ive never had any issues with the front tire pulling the valve stem off--just the back. The last time I replaced the tube, I also cleaned the tire bead. Since then I haven't had any issues (knock on wood). BTW I run about 50 psi........FWIW.

[Steve Swan]

I have read this thread and learned a lot from all your posts. I am currently working on a 26 BA/AA that actually starts and runs after sitting for 40-50 years. I starter another thread asking for help with clinchers but didn't get much response, so I thought i'd post here.
Now that the engine runs and all is there for it to ride, I decided that it needs to be able to roll....
I just started the project of removing the well worn and partially rotted rear tire. After reading the posts on tubes and pressures I was interested to see what was lurking inside the tire.
What I found (see attached picture) was a Firestone tube from? that had be patched at least 9 times with patches of various colors and dimensions. I was also surprised that the tube was designated for the tire size 3.85x18. Whoever had this bike used the tube and tire for all it was worth.
I have ordered replacement Cokers and welcome any advice on mounting them.

Ed

why not just use that tube....?

don't over think mounting the tires like i did. get tires as warm as possible, lying in hot sun good. Put them on by hand, dry. despite what others say, cut a tiny relief in edge of both bead sides for valve stem to protrude through. tape the valve stem to avoid scratching paint. put one side of tire on. put the tube inside tire. inflate the tube to push the bead across the hole in rim for valve stem, you might have to do this several times so valve stem can be put through hole. put on second bead, they sort of roll on sort of inside out, installing clinchers not the same as installing drop centers. the hotter the tire is the better your chances of mounting with hands only. if you don't seem able to get the last few inches of bead over rim, then tape any tool you deem appropriate for the job at hand.

if you don't care for my method, there's a number of threads on the forum to study or you can google videos off internet. one fellow mounts the tire using a plastic bag. apparently i'm too inept to do it same as he did it, all i manged to do was get in the bag and not the tire. ha.

[eddiepanhead]

I have read this thread and learned a lot from all your posts. I am currently working on a 26 BA/AA that actually starts and runs after sitting for 40-50 years. I starter another thread asking for help with clinchers but didn't get much response, so I thought i'd post here.
Now that the engine runs and all is there for it to ride, I decided that it needs to be able to roll....
I just started the project of removing the well worn and partially rotted rear tire. After reading the posts on tubes and pressures I was interested to see what was lurking inside the tire.
What I found (see attached picture) was a Firestone tube from? that had be patched at least 9 times with patches of various colors and dimensions. I was also surprised that the tube was designated for the tire size 3.85x18. Whoever had this bike used the tube and tire for all it was worth.
I have ordered replacement Cokers and welcome any advice on mounting them.

Ed

[Steve Swan]

Eric, thank you for your reply. i cannot remember where i got the motocross 4 mm tube idea, it was from somewhere, i am thinking this thread or the link on page 1 of this thread "OcchioLungo wordpress." Know that there are no 20" MX tubes available, so i fit a 19 inch tube, rather than a 21" tube, so that there is no bunching of the tube one could expect with a 21 inch tube. i will suggest the heavy 4mm thick tube will give a bit more sidewall inflexibility.....? thoughts anyone?

before i write further, i feel it necessary to state i am discussing solo riding the Coker 3.85x20 diamond tread clincher tire on a new Al McRoberts rim (and i weigh 180 pounds). (the Rider's Handbook refers to this tire as a 3.85x27 and the tire is also known as a 3.85x20) clearly blowouts are a worrisome concern for us folks who are willing to risk a "like original" accident due to a clincher blowout.......

and - i am not trying to over-think this topic, i am simply trying to understand what physical forces are in play on the clincher tire in it's under and over-inflated states. clearly my questions/musings may be the same to some as trying to figure out how many angels fit on a pin-head..... i just want to make sure i have done my due diligence by checking tire psi every time before i go out on a ride and what folks feel appropriate psi for solo riding should be. Considering the number of conditions that can contribute to blowout, i cannot help but wonder if clincher's are not getting an unnecessarily bad rap despite their inferior design.

the reason i am giving this thread a little CPR is because my local buddy is getting ever-closer to the day he'll have his 29JD on the road and he and i have had some back and forth convo's about clincher tire psi, i.e., follow Rider's Handbook settings, follow what other people are saying their experience is, over-inflate vs. under-inflate, so forth, so on. he has been told by a rider of recognition that 20 psi is all that is needed in a 3.85x28 (20 inch rim) and of course the Rider's Handbook says inflate front = 15 psi and rear 20 psi. (i have been running 40 psi in my tubes without incident thus far.) another reason for keeping this thread on life-support is there may be new experiences people can share since we last discussed the topic in 2012-2013.....

thoroughly reading the OcchioLungo article, it seems the consensus of the information in the article and folks with hundreds if not thousands of miles is a range between 40-45 psi.

again, what i have noticed absent in these discussions is:

1. the condition of the rim in which blowouts occurred ?
2. what psi guys were running that had these blowouts ?
3. what type of tubes were fitted in these cases of blow outs ?
4. what is the condition of the bead in which blowouts occurred?

Clearly, any one of these factors are critical and could cause a blowout, and any combination of these factors one could assume would even further increase the risk for blowout.

can ANYONE think of a good reason why the factory would publish 15/20 psi for the 3.85x20 tire ?? and why we are saying inflate to 40-45 psi ??

it seems reading this thread, there are at least four conditions that can contribute to a clincher blowout....
1. the tire rolls of the rim due to under-inflation....correct ??
2. the bead gets "cut" and simply pops off rim from under-inflation....correct ?? and..... WHAT DOES CUT MEAN ?? the bead actually is severed from the body of the tire...?? Would this "cut" be caused by a sharp bead edge of an old original rim...? or by any rim due to under-inflation....???
3. over-inflation, the bead literally blows off the bead....??
4. the valve stem severs due to under-inflation because the tire actually "walks" on the rim and as a result the stem shears at the point where the stem comes through the hoe in the rim...???

it seems obvious, in the case of under-inflation, the tire could literally roll off the bead, especially in corners. and i guess if the tire is under-inflated, as the tire is walking, especially if the bead is sharp, then the bead will get "cut" ?? in the cases where the tire blew off the bead of a parked motorcycle, what was the psi? What was the rim condition? Was the tire in hot sun and psi increased?

[exeric]

I never thought of motocross tubes, Steve. As I stated years ago, I've had a lot of trouble with modern tubes, and mostly on my bicycle. I now run a quality tube from a local bicycle dealer and have had fewer blow-outs. I'll look into the Malcolm Smith tubes.

[Steve Swan]

i realize this thread has been dormant for 5+ years, but it is still a good one. i am running 40psi in my 3.85x20 clincher Coker tires with a Malcolm Smith motocross tube on brand new Al McCormick rims.

Reading the stories of blowouts in the thread and the fine article, the one thing that is not mentioned is the condition of rims in the cases where blow outs occurred. Does anyone know of cases where blowouts occurred on new rims withe the heavy duty 4 mm motocross tube was fitted?

[Rod K]

Thanks guys....18 and 20 lbs. I'll just add a couple more lbs. I'm not in the 150 lb class anymore......Rod

[frichie68]

My VL Rider's Hand Book sez: Solo service
4.00 in tires (standard equipment) Front 18 lbs. Rear 20 lbs.
4.50 in tires (Special equipment) Front 16 lbs. Rear 18 lbs.
Supposed to be for an "average rider of 150 lbs."
Rich

[harleytoprock]

My 1936 riders hand book states 18lbs front, 20lbs rear for VL with 4.00 tires.

[Rod K]

Just for comparison...Anyone know what pressures the riders handbook gave for the VL's drop center rims??? I'm running
those on my 28J. .thanks Rod

[harleytoprock]

I was just looking at the 1929 Harley riders manual. The recommended tire pressure back then was 16 lbs front, 20lbs rear for a solo machine! This is for 3.85X20 tires. My 27' Jd feels better to ride with 30lbs than with 45 lbs. I do worry however, that the tires will fly off.

[pete @ occhiolungo]

yeah, I hear complaints about the quality of tires from Asia, and just as many complaints about the tires made by a certain US company too. But the Dunlops in the UK are made well, and are very tough. Not as sticky as the Cheng Shin type, but they last longer. Expensive, and hard to find too, but I don't have much choice on that. I use the ones that fit the rims the best. And that varies rim by rim, bike by bike, unfortunately. There were something like 27 different tire sizes in the old days, each with its own rim dimensions. But now we have to use what we can find. fun fun fun.

[Susanne]

45psi sounds good, but for what size tire, and under what load? Which factory book are you referring to?

Sorry about that - 28x3, under a Harley JD/FD, from their 1920-21 owners handbook... so between 300-400 lbs or thereabouts (likely the same as the henderson, as bikes then were thereabouts the same weight). Figuring a 9 sq. inch patch on the ground x 2 (I know its less, but that's what I was told to go by on autos, tho that's x4) 45 PSI x 9 Sq. inches x 2 tires... in theory it should handle 810 lbs total weight. I know there are other factors involved, but that would cover the bike and 2 riders, so maybe it's pretty close...

I had the scary experience of having a 30x3 1/2 tire let go near where I was standing - sounded like a gunshot!! It was also because of a pinched tube... I had a similar tire on a similar car (Ford T) that had been underinflated to 30 PSI (make that grossly underinflated by clincher standards) by the former owner (who ran it at that for a while, according to him) and it spun the tire, taking off the valve stem... What I noticed was the sidewalls (Older NZ Non-skids, IIRC from the 70's?) were severely damaged as well... like had the thing not gone flat from unstemmage (How's that for new terminology? ) and he then put the correct pressure in the tire (which is 60-70 PSI) the sidewall would have likely come apart...

It's also interesting to think that sidewall blowouts were apparently in the day not uncommon, and they sold shoes to fit over blown tires to get them to whereever... or home... or down the road. I also complain about the poor wearing quality of modern manufacture clinchers (from a certain southeast asian country) until I read the ads and realize high mileage then was 7500-10000 miles... so maybe it's not all that much different...

[pete @ occhiolungo]

45psi sounds good, but for what size tire, and under what load? Which factory book are you referring to? Excelsior recommended 45psi for it's circa 1917 bikes that ran 28x3's, but I haven't seen any factory literature for the earlier and smaller sizes. I've listed several sources from the 19teens and earlier in the article (linked above) that show various pressures for various tire sizes and various loads. 45 should be fine, especially for 28x3 with a heavy rider and passenger. But I wouldn't run more than that, and would use less with smaller tires, lighter bikes and lighter loads. For 24" and 26" tires, 30-40psi works well.

By the way, I had the rear tube pop the other day on my 1913 Veloce. It was the loudest pop that I've heard other than a firecracker or a gun. I wasn't on the bike, it was parked at the time, but I was planning to ride it in about 10 minutes. Close inspection showed a slight crease to the tube, where it must have folded slightly on a portion of the tire bead.

I'll repeat my advice: run what pressure you like, but check the pressures often, and do a good job during installation. And have fun out there!