Baffling 1970s British Wheel Engineering

I had a go at mounting new tires on the 1971 Bonneville project rims today, and what a pain in that ass that has turned into.  The rear tire is a mess of strange engineering decisions, including 3 holes for the inner tube valve, two of which are filled with rubber/metal pads with valve stem sized bolts sticking out of them.  Why they would do this is beyond me.  It creates a needlessly heavy wheel just where you don't want it (where centrifugal force amplifies it at the rim when it spins).  Perhaps it has something to do with the spokes and creating a true (round) wheel by adding weight?  The rear tire went on easily enough, but the inner tube was a pain to get the valve in place and it doesn't seem to be taking air.  I'll have to take that apart again and figure out what the hell is going on.

Also in bizarro British '70s engineering world, the front wheel has the valve stem hole drilled in the worst possible location, right near two spokes, which makes putting the compressor's tire inflation nozzle on it impossible.  There are spaces all around the rim where the hole could have been drilled to allow for easier access, but the Meriden Triumph 'technician' threw it in there.  If there is an engineering reason for it, it's beyond me.  Putting the hole in the space between more distant spokes shouldn't hurt the durability, but they didn't do that.

I've done inner tubes and tires for my modern Triumph Tiger recently, and just did a tubeless tire on the Kawasaki (complete with tire sensor hack), so this shouldn't have been the faff that it has turned into.  I ended up leaving both rims sitting in the garage.  I'll come back to it another day when I'm less frustrated by it.

Period tires from Revco look good on the rims, but the rear won't take air and I can't get any into the front.  Damn it.

Here's some old Triumph 'character' and a bit of moto philosophy to remind me why I'm doing this...

1971 Oil In Frame Triumph Bonneville Restoration: Tire Choices

The old Bonneville needs new tires and inner tubes so I'm wrapping my head around olde fashioned, pre-metric motor-bike tyre sizes.

Those would be the Dunlop K70s that came with the Bonnieville back in the day.
Fortunately Dunlop is still looking after the bike they designed the tire for.

The '71 Triumph Bonneville came with 3.25 X 19″ front & 4.00 X 18″ rears and used Dunlop K70 tires as standard equipment.

It looks like there are modern Dunlop options for vintage SAE (non-metric) wheels at Revco where I've gotten my last two sets of tires.  The handy chart below shows metric and imperial conversions but after some digging I was able to find SAE/pre-metric modern Dunlop K70s that are the exact fit for the bike.  Using recent versions of original equipment that give me the benefit of modern rubber durability and grip while still keeping close to the originally engineering intent in Triumph's tire choice is fantastic.  I'm not trying to recreate riding in 1971, I'm trying to start with that technology and update where prudent for 21st Century use.

  Tire Charts                               Motorcycle Street Tire Size Conversion Charts

Metric 80/90 90/90 100/90 110/90 120/90 130/90 140/90	Alphanumeric - NA- MH 90 MJ 90   ML 90 MN90/MP90/MR 90 MT 90 MU 90	Inch-(Series90) 2.75 3.00/3.25   3.25 3.50 4.00/4.25 5.0 - NA-	Inch-(Series82) - NA- - NA- 3.60 4.10 4.25/82/4.40 5.10 - NA-	Front Tires: Metric 80/90 90/90 100/90 110/90 120/80 120/90 130/90 Alpha MH90 MJ90 MM90 MN90 - NA- MR90 MT90 Inch 2.50/2.75 2.75/3.00 3.25/3.50 3.75/4.00 4.25/4.50 4.25/4.50 5.00/5.10	Rear Tires: Metric 110/90 120/90 130/80 130/90 140/80 140/90 150/80 150/90 160/80 180/55 200/60 230/50 Alpha MP85 MR90 - NA- MT90 - NA- MU90 MV85 MV85 - NA- - NA- - NA- - NA- Inch 4.50/4.75 4.50/4.75 5.00/5.10 5.00/5.10 5.50/6.00 5.50/6.00 6.00/6.25 6.00/6.25 6.80/7.00 7.00/7.25 7.90/8.00 9.50
Size 120/80V16 130/90H16 130/90V16 500S16 MT90H16 3.00 130/90H16 3.00 140/90H16 140/80VB16 140/90H16 150/80V16 160/80H16 160/80H16 200/60VB16 120/80V18 120/90V18 120/90H16 130/80V18 130/70VB18 150/70VB18 140/70V18 170/60VB18 180/55VB18 230/50 X 15	Rim 2.75 3.00 3.00 3.00 3.00 3.00 3.50 3.50 3.50 3.50 4.00 4.00 5.50 2.75 2.75 2.75 3.00 3.50 4.00 4.00 4.50 5.50 7.00 to 8.00	Overall Width 4.7 5.00 5.2 5.2 5.3 5.4 5.8 5.9 6.0 6.2 6.4 6.8 7.9 4.8 4.8 4.9 5.2 5.4 5.9 6.1 6.9 7.0 9.5	Overall Diameter 23.8 25.4 25.0 26.4 25.3 25.6 25.6 24.8 25.8 25.4 26.1 26.1 25.9 25.9 26.4 26.3 26.3 25.4 26.2 25.7 26.0 26.3 25.3

Note: Measurements are based on the given rim widths. A rough rule of thumb: Each additional 1/2-inch of rim width will be approximately 1/4-inch more in each tire width.

The K70s at Revco are just over a hundred bucks a pop and Counteract Balance Beaded inner tubes are actually cheaper than name brand plain old rubber inner tubes. I've been using the Counteract beads for years to great effect so they'd be my first choice even if they weren't cheaper. All in I'm looking at about $320CAN ($250USD) for new rubber for this vintage restoration project, which considering the price of some of the other parts is pretty reasonable.

In order to rebuild the wheels I'll need to replace the bearings and clean up the brakes before putting new pads and hydraulic brake cylinders back in them. All that and getting the frame sorted out will get me back to a correct rolling chassis ready for the upgraded engine.

Somewhere at the end of all of this will be a road worthy '71 Triumph Bonneville, but it's a lot of parts to find and get in and then a lot time in the garage to get there. I'm hoping it'll be on the road for next year's riding season.  As we thaw out here in Canada I'll be out on the Tiger and GTR and not spannering so much.

Meanwhile, here are some more motorcycle tire sizing reference charts found on the interwebs:

DIY Motorcycle Tires

My first go at motorcycle tires way back with the Concours left me with a staggering dealer bill for nearly $700 for two tires installed.  That made me a bit jumpy about moto-tire changes.  Last time around I did a pair of Michelin Anakee 3s on my Triumph Tiger.  For that one I purchased the tires online and got them installed at my local shop.  That cut the cost down to just over five hundred bucks for two tires installed which is the way to go if you don't want to get your hands dirty, though I still did in both cases because I had to take the tires off the bike to get the professionals to do the job.

This time around I thought I'd order in the tires and do them myself.  I did a lot of tire changes as the tire guy at Canadian Tire during my misspent youth and know the process, but I don't have any of the pneumatic tools at home that made the job quick and easy.  A good piece of advice came from buddy Jeff, who suggested it's a good idea for anyone who rides to do their own tires at least once so you're not doing them on the side of the road for the first time, or getting taken to the cleaner by a shade tree mechanic who sees you coming from a mile away.

Doing tires by hand is easy if you do a couple of things to help the process.

Make sure you've got your direction of travel
worked out - bike tires aren't obvious in terms of
direction of rotation like cars are.  I should have
looked at which side the speedometer was on
but got distracted by just getting the new tire on.

When I couldn't get the old tires off at home I took them in to school and the auto-shop teacher and I did the job, but in the process of putting the tires on we must have got the front turned around and ended up installing it backwards.

It was a sweaty job the first time so I wasn't looking forward to doing it all over again, except this time I had a couple of tricks in hand to help things along.

Tire Installing Hack One:

Warm up the tire! It's Canadian winter here and cold tires are way harder to take off and put on.  This time around I left the tire on the rim on a heat vent by the front door before taking it out to the garage.

Warm tires are much more malleable and easy to dismount and mount.  If you're working in a cold garage this becomes doubly important.

Tire Installing Hack Two:

Use a lubricant to help the tire slip on the rim.  We used soap and water in the shop at school but I had an old bottle of Armour All sitting in the garage and used that to great effect.  A moisturised tire stretches more willingly and pops off the bead and back on again much easier than a dry one, and Armour All did the trick even better than soap and water.

Tire Installing Hack Three:

Be especially careful about inner tube placement if you've got them in your tires.  Pinching one can take you all the way back to step one again.  It's easy to get them seated inside the rim well away from the bead, but if you rush you can make problems for yourself.

Tire Installing Hack Four:

Save yourself the costs and logistical headaches of getting your new tires in for balancing by using Counteract Balancing Beads.  I've used the balance bead kits in tubeless tires with excellent results, so this time I got the Counteract inner tubes that include the beads inside.

I've installed bead kits into inner tubes before but it's a fiddly process (easy on tubeless tires though).  The kit that included new inner tubes for my 17 year old ones was a good choice that wasn't much more expensive than a new inner tube without the built in balancing.  Don't be skeptical about Counteract bead, they work!

Tire Installing Hack Five:

Get yourself some good tire spoons.  I got this Neiko long handled spoon set from Amazon and they've been good tools.  They're tough, built to purpose and the long handle gives you ample leverage.  At only $35 for three long handled spoons and the rim protectors, it's also an inexpensive way to make a hard job easier.

Using the first spoon to pry the tire off the rim, you can then work your way along keeping one in to hold the tire off the rim while the other two work together to work the edge of the tire off.  Soon enough (especially if things are warm and lubed), you've got the tire free.  They've installed 3 tires already (the front one twice) and still look brand new.

Thirty-five bucks in tools and a couple of common sense steps and this time around my tire change cost me $460 which included the two Michelin Anakees and Counteract beads delivered to my door.  Looking at those Michelins that cost me a fortune dealer installed way back when, I can see the same tires with Counteract beads delivered to my door for $462, or about $240 less than what I paid four years ago.

DIY tires are the way to go as long as you've got the right tools and know the tricks.  And if you're ever struck on the side of the road you'll know how to get into them and patch up the inner tube because the mystery will be gone.

Rubber Maths

I've looked into the savage world of motorcycle tires before.  Way back in 2016 I got fixated on customizing the rims and putting new rubber on the Kawasaki Concours, and got introduced to the expensive nature of buying half as many tires that wear out way faster.  That first time left me with a $500 bill for getting 2 Michelin Commander sport touring tires installed and left me wary of the expense.

More frustratingly, I ended up using the Counteract balance beads anyway because the caveman weights used on a traditional balance machine still left the wheels with a wobble, so that $500 bill ended up being even higher, though it did make me feel way better about using those beads - they work better than weights and a technician half paying attention to the balancing machine.

In 2017 the Tiger's tires were getting tired, so I was once again at Two Wheel trying to get in for service (they suggested a one month wait was likely that time - local car tire places really need to look into this market).  At that time they were pricing Michelin Anakees at about $420 for both, with another $100 for installation which was only the tires because if I wanted service within a week instead of a month I had to remove the tires and bring them in myself.  With taxes and incidental costs that crept in on the bill, those two tires ended up costing me almost seven hundred bucks, and I had to take the damned rims off and put them on myself!

Fast forward to 2020 and supply chains are in tatters (not that they were that good a couple of years ago).  After trying to contact Two Wheel and getting no response to multiple attempts, I started looking elsewhere.  No local tire companies do motorcycles - you're missing a market there everyone.  Motorcycle tires wear out quickly, get replaced often and cost more!  The only motorcycle focused company that could be bothered to raise a response was Revco, who were responsive and delivered the tires quickly and efficiently, even beating expectations I'd have had pre-pandemic.  If you need motorcycle tires in Canada, Revco can and do deliver!

Where am I at with costs this time around during a pandemic?  Counteract Balance Beads were just under thirty bucks, the two tires were $126 & $155, so the whole bill came out to $310.  I'm at $360 including taxes and delivery.  Lloyd at my local independent motorcycle shop, Mostly Ironheads, installed them for $100, so now I'm at $460 for this round of motorcycle rubber.  That's 35% cheaper than my last pre-pandemic tire buying experience.

Just out of curiosity I looked up the same Michelin Anakee tires I put on the Tiger three years ago that ended up costing me $500 just for the rubber.  They're starting to square off and have a fair number of kilometres on them, so an over-winter tire change is likely this year.  On Revco three years later they're $382 delivered with taxes, or 24% less expensive.  Even Lloyd's newly updated shop costs for installation at Mostly Ironheads are less than dealer costs in 2017, and are done in a day with the same amount of fuss (I still have to remove the wheels).  I'd be at $482 ready to roll when it cost me $700 three years before.

I know where I'm going and how I'm getting tires fitted from now on - and I'm even supporting my small, locally owned shop in the process.  The only thing preferable would be my own tire installation machine, but I can barely fit in the garage as it is, so that'd only come after a house move.  With the deficit in service around here, maybe I should just be doing motorcycle tires out of my garage anyway.