Heavy braking questions

[OldNick]

I have been practising heavy braking on my '98 Valk trike. By heavy I mean to the point where the tyres are just, just scrunching before skidding. So, as hard as as I can. A couple of questions if I may.

Firstly I was surprised by how easy it was to lock the front wheel, if it was not rear-assisted. It has been commented that being a trike it would be like that. But since this is basically a bike with a rear end and not a whole new frame with the motor slung out the back, I would have thought there was still a fair bit of weight on the front. Even the rear axle and diff are only _on_ the rear axle and not behind it and the engine is still forward. I know that proper braking consists of using the rear to throw the weight on the front, as well as aiding braking, but I was just trying it out to see and I am a bit puzzled. The beauty of a trike is that a front wheel lockup is just a problem and not end - game

I will add that with 265 rear tyres, pumped at about 12psi, they grip like the proverbial to a woolly blanket!

Secondly, under really heavy braking, I find myself diving right or left (no preference, so it's probably not the brakes causing it). I can see that throwing weight on the front forks is going to bring the front down and ruin the rake and trail for directional stability, There is no play in the forks or anything like that. Is this a bit of a trike thing? On a bike, you can be transferring weight all the time to counteract that and maybe I just need to learn the new feel. The Valk has a solid swing arm, not any sort of independent suspension,and I find that this will tend to pull you about a bit on the bumps. Being a total trike noob, that has taken getting used to. It's not a killer, but I have to be conscious of it when braking hard. I suppose with practice it will become second nature, but I was just wondering.

Thanks for any input.

Nick

 

[mhgoldwing]

First of all, braking on a trike is not that different than a bike. Technique is key here and the prime ingredient is to "squeeze" the brake levers. It's fast but it is a squeeze rather than a "grab".

From 20 mph do this: gradually start squeezing the front brake lever and continue increasing the force applied until just before the tire breaks loose. Be sure to keep the trike in a straight line. What you will notice as that as force is increased the front will go down shifting weight onto the front wheel which provides traction.

By the same token when this same technique is applied to the rear brakes while also using the front brakes, assuming they are not linked, you will have to ease off sooner because the rear end wheel lighten up. It will not lighten up as much as a bike though. Those big tires have a lot of grip and stopping power if you keep the trike "balanced" from front to rear, allowing both to gain maximum stopping force. It takes some practice using both but they will haul your trike to a quick, positive stop.

 

[SMSgt]

First of all, braking on a trike is not that different than a bike. Technique is key here and the prime ingredient is to "squeeze" the brake levers. It's fast but it is a squeeze rather than a "grab".

From 20 mph do this: gradually start squeezing the front brake lever and continue increasing the force applied until just before the tire breaks loose. Be sure to keep the trike in a straight line. What you will notice as that as force is increased the front will go down shifting weight onto the front wheel which provides traction.

By the same token when this same technique is applied to the rear brakes while also using the front brakes, assuming they are not linked, you will have to ease off sooner because the rear end wheel lighten up. It will not lighten up as much as a bike though. Those big tires have a lot of grip and stopping power if you keep the trike "balanced" from front to rear, allowing both to gain maximum stopping force. It takes some practice using both but they will haul your trike to a quick, positive stop.

:Agree: Well said.

 

[keepinon]

Nick, I, too, have a '98 Valkyrie trike, w/straight axle. If I find myself being "pulled" one way or another under heavy braking, I've found that one rear wheel is braking harder than the other. Usually manifests itself as a skid on one side. When the brakes are adjusted even, I have no pulling, and if hard enough to skid, both do.

Over the years, I have found the right side brake (on mine) brakes a little harder than the left. I just assumed because it was closer to the master cylinder, less line for the fluid to travel. Anyway, I always set my left brake shoes two notches tighter than the right... seemed to fix the problem.

And I had those fat rear tires on mine.. until I rode on wet roads. They brake well when dry, but sure do hydro-plane (maybe float ) on wet roads. But, you may be in one of the more arid regions.

 

[OldNick]

Nick, I, too, have a '98 Valkyrie trike, w/straight axle. If I find myself being "pulled" one way or another under heavy braking, I've found that one rear wheel is braking harder than the other. Usually manifests itself as a skid on one side. When the brakes are adjusted even, I have no pulling, and if hard enough to skid, both do.

Over the years, I have found the right side brake (on mine) brakes a little harder than the left. I just assumed because it was closer to the master cylinder, less line for the fluid to travel. Anyway, I always set my left brake shoes two notches tighter than the right... seemed to fix the problem.

And I had those fat rear tires on mine.. until I rode on wet roads. They brake well when dry, but sure do hydro-plane (maybe float ) on wet roads. But, you may be in one of the more arid regions.

Yeah that was my first thought, but then the trike pulled the other way and fater that it was sort of random.It may be that one brake is pulling and I am over compensating.I need to have another look.

Nick

 

[cavie]

Rear tires at 12lbs???????????? Way too low. Your gonna heat em up and wear em out. Very dangerous. 20 lbs is the min. I would go. That's what I run with my 05 VTX Champion SA.

 

[OldNick]

OK I will check again with the previous owner, who has clocked up over 100,000 Km on the trike.Not all on these tyres I assume, but he does know what he is talking about I reckon.

Nick

 

[OldNick]

OK. I checked with the previous owner and he says that because there is not much weight on them that's what he was told.I have gone to 15PSI. BUT I did find that the front tyre was at 25PSI...now it's at 42 and it's a new trike under brakes. My only excuse is rustiness and a whole heap of stuff to worry about on the trike, for rego.

Nick

 

[cavie]

Check with the manufacturer. 15 is still too low. 20# is the min I have seen by the collective of this board. 20/24 seems to be the answer.

 

[OldNick]

OK. I am not just digging my heels in on this. I am listening to ideas. As you guys suggested, I tried Yokohama and they referred me (back) to the guys who are doing my rego (which it failed , leaky front forks that ONLY showed up when I took her in down the slightly rough highway). He said one of the first things he checked was the wear on the tyres and said it was very even and therefore pressure was about right for the load. He in fact suggested I run them back down to 12PSI and run them at 12-15 depending on load. He said it's really tough with car tyres on a trike, because withg the light loads they do not heat up and squirm as much, and wear was how he judged it. The guy is an accredited vehicle examiner and an ardent chopper builder and modifier, who also knows trikes. His life is motorcycles. I am not going to argue with him.

Nick

 

[Red Wing One]

Gooday Nick, I'm not a trike expert (far from it) nor a tire expert, but I'd like to quote my Lehman Technical manual provided to me with the trike.
When John Lehman began building trikes over 25 years ago, he and his colleagues experimented with tire pressures and found the optimum pressure for the rear tires to be between 20 & 22 PSI (actually it might have been lower, but tire manufacturers set the minimum pressure standard at 20 PSI).
This was the Lehman recommendation up until around 1999 when they were advised by the tire manufacturers to increase the minimum pressure to 25 PSI per their revised standard.
The standard was changed after law suits Ford and Firestone endured after the rollover issues with the Ford Explorer.
Owners of Explorers were reducing their tire pressures to improve ride quality, but failed to increase the pressure when they increased the load in their vehicles. The top heavy Explorers were prone to rollovers under these conditions.
I personally will let my rear tire pressure go as low as 18 PSI only because that is my comfort level.

Best regards.........Marcel

 

[Solidbob]

Me Too..... I don't own and Explorer but if I did the tires would be aired up enough to prevent roll for the weight being carried...

Some folks have just lost a few logs off their stack of what was issued to them!!!!!

 

[OldNick]

OK Marcel. I take that on board and I will see how it goes. If I feel insecure I will up them a bit. This is NOT an Explorer though

Nick

 

[JaysGone]

At 12 psi the tires heat up a lot more then they would at a higher psi. While maybe not affecting your braking much. They will wear prematurely for sure.
My trike would spin them off the rims at that low a psi.

 

[OldNick]

OK. I am going to unsubscribe. I am sorry.These tyres have not been spun off the rims. And bear in mind that....heavy braking...will exert MANY times as much force as any acceleration that the vehicle is capable of. The wear patterns indicate that they are well inflated. The previous owner has travelled many thou Ks on them at 10-12 PSI,. He was told to use that PSI. The bike-freak vehicle examiner said the wear pattern was good and said stay at 12-15 PSI.The tyres do not bulge. The MAXIMUM load on each tyre would be 200Kg as distinct from what....5-700Kg on a car?

IIRC I never asked the question about inflation( ??) I simply commented that they stuck like shit to a blanket on the road under brakes. So I am going to stay where the previous owner was while travelling 10'thou Ks all over Australia...a lot of it on these tyres.

 

[FRR]

10-12 LBS in rear tires???? Not good practice. Period.

 

[Solidbob]

Tires have ratings for Min. & Max. Inflation on an automobile if it an automotive tire. Every Manufacturer has this information about every tire they build... its the law in the US and should be on the sidewalls for all to see!!!