Tire/ Wheel selection

tech.tmr11 wrote: last time we used locknuts....no problem with that....

Using a normal nut when you need a tapered one would be inviting disaster. Your wheel would never be concentric.

One option if you need tapered lock nuts is to make tapered washers and the use a normal lock nut. Wouldn't be too hard to drill out a tapered nut and cut it down to turn it into a tapered washer.

Akron 1998 to 2004 wrote: Wheels:  I'm guessing its because of price but I'm a bit surprised we were the only Baja team that seemed to us Keizer Wheels.  They are heavily used in SAE Formula.  If you can find a Douglas rim in the size you need, they're cheaper.  But for a little more $ Keizer will make a rim in any bolt pattern, diameter, width, back spacing you want.  You can get absolutely zero scrub radius with custom back spacing!  Don't know what the current pricing is like but a custom rim with dent rings and mud cover cost about $120 back in the day.   http://keizerwheels.com/

Edited by tp - Mar/14/2011 at 3:45pm

Most tapered lugs are 37 degrees (I believe). You would need a pretty massive lock nut to put that sort of taper on it.

tp wrote: Most tapered lugs are 37 degrees (I believe). You would need a pretty massive lock nut to put that sort of taper on it.

 

Akron 1998 to 2004 wrote: tp wrote: With the demands of todays racers, you can get a Douglas wheel in almost any backspacing that you can dream of. Not only that, but personally I don't know how much I'm going to trust a road wheels with what we do. I've seen our Formula team break wheels. Judging by how many wheels I've destroyed, Baja just demands something stronger. If you have a properly designed suspension, you can get a zero scrub radius with whatever wheel you choose. Like maybe something off the shelf. EDIT- didn't realize that Keizer makes quad wheels too. Thought it was just sprint car and road wheels.   Douglas wheels are almost all spaced 3" in from the outside.  Keizer will make you one spaced 0".  That means your custom A-arms can be 3" longer, better angle on the ball joints, more travel, what ever you want to design, etc.  Keizer makes nice spun metal race quad wheels.  Never damaged one with a anti-dent ring.

Edited by dillon_b12 - Mar/14/2011 at 6:26pm

Greenreed1936 wrote: We have run Keizer wheels for the last 5 or so years and just now had one destroy itself at Michigan Tech's Winter Comp. They hold up to the abuse quite well.  A little spendy but perform very well.

To be fair, that wasn't really the fault of the wheel...

tp wrote: You can backspace Douglas wheels 1, 2, 3, 4, 4.5 or 5 inches. The problems is if you got too much one way or the other you end up putting lots of stress on your wheel bearings.

Just in case any one is interested.

Edited by Akron 1998 to 2004 - Mar/18/2011 at 12:20pm

We have used them for our rears for our last 3 competitions and the only flat we had was due to a massive impact that also dented our trailing link, bent the lower camber link pretty bad and sheared the driveshaft...

I do not exactly know the typical values for rolling resistance of a Baja tyre but however, based on my experience, they must be in the range of 10N - 150N. Please keep in mind that rolling resistance is a function of the vertical force, inflation pressure and forward speed of the tyre and hence I have expressed it as a range. 

Edited by sujandinesh - Jul/18/2018 at 3:58am

The static friction of what? 

Bantu wrote: Hi I am working on the Mini Baja from South Africa. The total weight of the mini Baja including the weight of the baja is 310Kg. My aim is to archive the maximum velocity between the range of 50km/h-60km/h.But I only managed to archive 44km/h by calculations. My question is, when I calculate the resistance forces, should I consider both Static friction and Rolling resistance friction? In my calculation I considered them both and I found that, the static friction has a very huge negative impact towards achieving my goal. Now I am not sure if I should take the static friction into account.

I hear u but my question is, which friction must I use in my calculations between static friction resistance and rolling friction resistance?

Yes. For example: F_static = u*N, where (u=0.4) static friction coefficient and (N=310kg*9.81) normal force. Therefore F_static = 0.4*310*9.81 = 3041.1N. And F_rolling = u*N, where (u=0.02) rolling resistance coefficient and (N=310kg*9.81) normal force. Therefore F_rolling = 0.02*310*9.81 = 60.822N.

Remember there is also an air drag resistance force that I have to add on these two forces.

My question again, do I add Air drag resistance force with rolling resistance force or Air drag resistance force with static friction resistance force or I have to add all three resistance forces in order to get the total resistance force for an accelerating Baja from rest on a flat level track??

Thank you for your explanations but you still have not answered my question.

Thank you