Topic: Triumph Trident rim locks

[red2002]

Sort of non-SOHC, but bear with me:

I'm in the process of restoring a 1972 Triumph Trident and upgrading to a pair of spoked alloy rims.

The Tridents came with rim locks on their rear spoked wheels to both prevent tire slippage, but more importantly, to keep the tire from parting company with the wheel in the event of a moving blow out.

The bike might have 50 horsepower to the wheel on a very good day, so I can't imagine that it could make the tire slip. Several people over on the Triples Online site say that they have had nasty blow outs at speed and the rim locks saved their hide.

My question is, how did the Honda 750's, Z1's and their ilk not use rim locks? All ran tubed tires with spoked wheels, just like the Triumph; just as heavy, with more power.

Any thoughts on this?

Thanks!

[bwaller]

They are an absolute nuissance and in my opinion completely unnecessary. Old school stuff.

[paulages]

I've got a pile of them in my Norton, BSA, and Triumph spare parts bins...I've removed them from every British wheel I've come across. Definitely unnecessary. They're all yours if you want them! 

[medic09]

Yep, my '75-waiting-to-be-rebuilt (stuck on electrics and ignition) has rim locks.  I didn't know what they were.  The PO, and old gentleman who used to race bikes and cars, gave the same reasoning you mentioned.  Said they were needed back then.

You ask a good and rational question.  My '78 Honda has never needed them.  Why was this a British thing?

Red, I'd be real interested in following your project.  Are you posting it anywhere?  I've not been to Triples Online in a long time.

[dave500]

you might use them on dirt bikes if your running a real low tyre pressure.

[red2002]

Thanks to all who replied.

I'm planning to deep-six the rim locks and use Buchanan's Sum WM3 rims on both ends. They will drill for a rim lock hole as an option and I'll ask them for an opinion, as well.

I agree that a blow out at speed with the tire departing the rim would indeed be a bowel-emptying experience, but again, why didn't the Japanese bikes need the locks on their big bikes?

Can't recall that the big BMW GS bikes with spoked wheels use rim locks and I think they use tubes. Surely today's rims with modern tires are superior in this regard over their 40-year old predecessor.

No, I'm not posting the project's progress anywhere, but I'll share what I know. Shoot me a PM with your e-mail address and we can compare notes, if you want.

Talk about a love-hate relationship: I was fed-up and ready to part the damn thing out on eBay, or possibly set it on fire, when I finally got it running again

After 21 years of ownership, I've now sunk so much money in it that I have to finish it.

I am hopelessly hooked.

Mike

[MCRider]

you might use them on dirt bikes if your running a real low tyre pressure.

That's the deal right there. Lots of off roading and/or poor roads back then. Low tire pressures and slogging thru mud would spin the rim in the tire.

As far as the Japs, my 68 CL77 (305 Scrambler) has them the 68 CB77 (305 SuperHawk) does not. Street Tires not exceeding age limits and with proper inflation seldom if ever blow out, like never. I'd be curious if the tires you heard of blowing out were old and decrepit.

[Hinomaru]

My first big bike was a 1965 Triumph 650 with the rim locks and they were referred to as "security bolts" in England.

Way back in the day many riders carried patch kits, pumps and tire irons.

In the event of a flat, the rim lock keeps the valve stem from being ripped out of the tube. This usually happens when the rider applies the rear brake too hard in attempting to stop quickly. A ripped tube cannot be patched along the side of the road and the rider was stranded.

Also, the local Triumph-Norton-BSA dealer used the rim locks as a selling point. Saying that locks were needed because the Trident and Commando engines were powerful enough to spin the tire on the rim. Of course this was pure marketing hype, but those bikes could run with the Honda 750 down the quarter mile.

[crazypj]

Personally, I think it's a US/liability thing.
 The big 4 had multiple dealers and service intervals which were mostly adhered to.
 People who didn't service bikes correctly (ie most 'customers) would have problems.
If suspension is 'too hard' what do people do?
 They reduce tyre pressures to compensate 
British bikes also used lower minimum pressures as tyre sidewalls were pretty stiff back then (UK Dunlop or AVON)
I know pressure recommendation for my 1952 A10 is only 19PSI 
 You know it's still a problem, several million upside down Ford Exploders can't be wrong 

[754]

It may be to get you home and prevent tearing out the stem.

 About 3 weeks ago I removed a used 400 x 18  universal tire from a Yamaha mag, and intalled it on a 754.

 I bounce tested the tire, seemed to have enough air, so I started riding it. Of couse I left the valve stem lock nut loose. I ran it about a week, then came out from coffee to a flat tire.. >:
 (   I started it, tried to ride it got about a hundred feet, and in that time it was swapping sides, and I could hear the rim hitting the pavement. no way I could have ridden on that. A blowout on that would be fun , its still on there.

 On my street racer 836, I drilled the stock 18 and run 4 sheet metal screws on each side.. thinking of putting it back on..

[srook]

"My question is, how did the Honda 750's, Z1's and their ilk not use rim locks? All ran tubed tires with spoked wheels, just like the Triumph; just as heavy, with more power."

The answer to this is the reason the British manufacturers aren't around anymore.  Honda and Kawasaki were using brand new clean sheet designs built in modern factories with new tooling.  Triumph and Norton were using essentially old designs and updating them as needed to produce new models.  The Trident is essentially 3 Triumph 250s fit into a common crankcase not to mention the frame and cycle parts were based off old sheet designs and were made with tooling from the 1930s.  The Triumph Speed Twin and TR5 of the 30s and 40s had rim locks therefore the T150/T160 of the 70s had rim locks.  That line of thinking was a direct result of the ultimate failure of the British motorcycle industry.  The CB750 didn't kill them off, they failed to update their processes and factories as well as their thinking.  The CB750 just made them not be able to cover their expenses after 1971 and scale back production which resulted in layoffs, the closure of BSA and the British government's bailout and forced merger of Triumph and Norton.  Different story for a different forum.

Scott

[medic09]

No, I'm not posting the project's progress anywhere, but I'll share what I know. Shoot me a PM with your e-mail address and we can compare notes, if you want.

Talk about a love-hate relationship: I was fed-up and ready to part the damn thing out on eBay, or possibly set it on fire, when I finally got it running again

After 21 years of ownership, I've now sunk so much money in it that I have to finish it.

I am hopelessly hooked.

Mike

PM sent.  Maybe you'll be our inspiration.  The wife and I are supposed to be working on the T160 this winter.   

[HawaiiMike]

I have an old KZ1000 rear wheel with two rim locks on it too.  Can't imagine that it would need them.

[red2002]

HawaiiMike,

Wonder if your Kawasaki's rim locks were added by the previous owner, a paranoid, old Brit-bike guy?

To satisfy my curiosity, I'll have to research to see what other street bikes used them.

The very knowledgeable guys on Triples Online tell me that the locks will prevent the tire (tyre) from coming off the rim in the event of a moving blow-out. Several of them report that they have experienced this thrill firsthand and none wishes to repeat it.

I've decided to not use the rim locks on the new rims and keep a close eye on my tire pressure, taking my chances.

This bike will pull amazingly hard for an old bike; cornering clearance is pretty limited, and it's easy to deck the non-folding pegs.

Work on one of these, then look at its contemporary, your SOHC and see why the old-guard British bike industry wound up where it did.

Mike

[crazypj]

I have an old KZ1000 rear wheel with two rim locks on it too.  Can't imagine that it would need them.

Don't remember them having 2 stock on 1000, thought it was only the early 900?(but it's a long time since I worked on one)

[srook]

"Work on one of these, then look at its contemporary, your SOHC and see why the old-guard British bike industry wound up where it did."

I think you're way off base here.  BSA Group spent itself into oblivion and did not have the sales to cover their expenses in 1971 for many reasons.  The CB750 played a role in offering an alternative to the Triumph/BSA Twins and Triples.  One Triumph dealer in MA had orders for more Triumph twins in 1971 than any year previous.  The problem was that the bikes didn't get into the dealers until late August.  By that time over half of his orders had been canceled.  I believe that Triumph if not the entire BSA Group would have survived if they had been acquired by a larger entity like Harley Davidson with AMF.  Anyway here's a nice ad by the Triumph that features both bikes.  I don't know if it's genius or madness to feature a full page of your competition in your own ad.




Scott

[red2002]

srook,

Great ads! Thanks for posting them.

I may well be off base, but here's my two cents:

Back when I was a kid in the '60's, the cool guys rode BSA's, Triumphs or Harleys. A "big" Honda was a 305 Superhawk.

I will never forget the first pair of Honda 750's I saw, one red, the other teal, owned by two brothers. HUGE bikes (at least compared to my 175 Bridgestone) with a disc brake, overhead cam, electric start. They didn't leak (horizontally split cases), vibrate and were faster than stink. Suddenly, the cool Sportsters and 650 Bonnevilles weren't quite so hot.

One of my friends bought a 650 BSA with the infamous timing problem, wherein it tried unsuccessfully to compress the combustion explosion. It looked crude next to the SOHC. It broke down a lot. It leaked. You tickled the carbs and ran gasoline all over the engine, your hands.

A few years later, I drooled all over the showroom floor at the new DOHC Kawasaki Z1 that out Honda'd Honda.

With the introduction of the Honda 750, who wanted a bike that leaked oil from even the headlight, was kick-start, vibrated, was slower?

Harley has built an empire selling nostalgia. After the introduction of the Honda 750, Triumphs and Beesas weren't nostalgic or fondly remembered, they were just old. We wanted the new stuff!

That new Honda was a quantum leap that blasted the bikes from Meriden to oblivion. Without their financial incompetence and labor issues, would NVT have survived? Would the new products in the pipeline (with overhead cams, by the way) have saved them? Dunno.

40 years later, I am nostalgic about my '72 Trident, as it reminds me of my youth and what the cool guys rode.

Despite now having a Triumph, I have given up all hope of ever being cool.

Mike

[dave500]

that bloke in the ad with the honda is a nicer guy though,ive seen even restored english bikes leak,at a gathering a few weeks ago in the british section one was leaking so much a large rag had to be placed under it,none of the old jappers leaked and every bike had been ridden there.

[srook]

Yes they leak and a properly restored bike leaks as well unless you use gobs of sealant which the factory never did.  If they leaked new a restored one should probably leak as well.  Remember Honda was using clean sheet designs not updating old designs to come up with new models.  

The British companies simply didn't have the resources or the desire to build brand new clean sheet motorcycles.  Look what happened when they tried.  Norton tried to team with Cosworth to build a road going twin 750cc with 80 hp.  Quite simply the Cosworth project bankrupted Norton and did not result in a usable motorcycle.  Triumph and Norton each tried to build a rotary power motorcycle that didn't see the light of day until the mid 1980s and even then it wasn't really a street bike.  Triumph tried to build an overhead cam twin code named the Diana in the late 1970s but the project never turned into a usable motorcycle.  John Bloor's team assessed the Diana when he aqcuired the rights to Triumph in 1983 and they rejected it as unreliable.  They chose instead to start from scratch.  

The British bike industry did not fail becuase the products were undesirable.  In fact the Trident and the Commando can beat a CB750 in the quarter mile.  How many AMA championships were won on the back of the CB750?  How many Isle of Man races were won by the CB750?  How much was cost a factor in a customer choosing a CB750 over a Trident, Commando, or Bonneville?  Honda used the CB750 as a loss leader in the U.S. to undercut the British bikes.  In Britain, the CB750 was priced higher than the Triumph Bonneville or Trident.  In fact, according to Classic Bike, the best selling 750 of the 1970s in Britain was the Triumph T140 (Bonneville).  It outsold the CB750K and CB750F combined.  And yes, it leaked oil.

Don't get me wrong I own a CB750 and can really appreciate all it has to offer but my Bonneville is just as quick and can handle like no other vintage bike on the road.  When I park it I have to stop myself from looking back at it becuase it just looks like a motorcycle should, slim, athletic, and little agressive.

Mike the Triumphs, BSAs, and Nortons that looked old in the 1970s could have built a future on nostalgia.  The new Triumph's best selling model is of course the retro styled Bonneville.  The new Norton while wearing modern bodywork still has the vintage Norton engine look and peashooters just like the Commando.  Alot of people realize that its hard to use 100+ mph on the street and can appreciate a bike that looks awsome and can get you from 0-90 in just about the same amount of time but can't run at 120+ all day.

Scott (who can't help himself)

[red2002]

Hey, Scott, great reply and well-taken points.

The Isle of Man - Slippery Sam owned that race. First production bike - a Trident - to lap at over 100 mph. "TT100" tires were named in its honor.

Of course, you already know why they named it "Slippery Sam."

I remember reading someone actually spinning the oil leaks into a good feature, as they "kept the undercarriage from rusting..."

"If it stops leaking, it's empty."

"Lucas: The man who invented darkness."

"Know why the British drink warm beer? They have Lucas refrigerators."

For what it's worth, my Trident shares the same black and red paint scheme and flow as the one in your ad; think that one's a '73, first year for the disk brake. Had it for over 20 years, ground-up restoration.

They are pretty bikes: clean, classic lean lines.

Will you post a pick of your T140?

Would love to have a '73 Norton 850, black and gold, last year of the right-side shift.

Seriously, you fit the ad copy's description of the "Triumph owner."

Now, excuse me, I'm gonna go tickle my carbs and dribble gas all over the place.

Mike

[Terry in Australia]

One of my old Commanding officers had a beautiful Triumph T160 and I was surprised that it didn't drop any oil, he told me that he'd learned very early in life that if you had the vertically split crankcase halves mating surfaces cleaned up on a surface grinder you can just about get away without any sealant at all.

Honda was smarter using horizontally split cases with all it's SOHC4's, there was much less chance of oil leaks when essentially your bottom crank case half is pretty much a "bucket". The Trident and BSA Rocket 3 were fast bikes, I knew a guy in Sydney (Lenny Henderson-Smith) who embarrassed Honda and Kawasaki's finest at Oran Park on many occasions with his home-built Trident racer. (that didn't leak oil either) Cheers, Terry.        

[d3buttz]

water sucks, gatorade is better

[srook]

Here's my 1979 T140E Bonneville.  I restored this bike about 12 years ago and it has held up well.



Here's my current build.  Its a CB750 with a full Dunstall kit.  I need to get it painted over the winter and have the mufflers re-chromed.  



Any pics of the Trident?

Scott