different spindles different handling?

[C41Xracer]

ive been wondering something for a while, are there different handling advantages to running a different spindle? Honestly are the trx450r or LT450r spindles better than the 250r spindles? Im not worried replacement parts, is there an advantage to running a different spindle and if so why.

[Honda 250r 001]

Heres my oppinion on this.

Unless your running the TRX 450r, or the LTR450 steering stem, theses spindles are not going to perform at their best. They were made to run on the 450's and have different geometry than the 250 has. I would stick with a good set of 89 spindles if your looking to race this, if your looking for a put around on set up, the 400ex, 450r would be a better idea IMO.

[C41Xracer]

what would the stearing stem have to do with the way the spindle performs?

[snacob14]

the angle of your tierod will affect bump steer and steering binding. Steering geometry through the years changed so mixing and matching parts may hinder handling.

[C41Xracer]

that makes sence

[Honda 250r 001]

Originally posted by C41Xracer
that makes sence

I wish we could get some custom aluminum stock 250r geometry spindles made that accepted 450r calipers. I believe Troy (troybuilt) had a pretty good spindle drawn up for the 250r :devil:

[troybilt]

Originally posted by Honda 250r 001
I wish we could get some custom aluminum stock 250r geometry spindles made that accepted 450r calipers. I believe Troy (troybuilt) had a pretty good spindle drawn up for the 250r :devil:

yea, I have a billet set modeled up, drawn and ready to go, ran into a snafu trying to get a set of them made... so I was sitting on the design for awhile, and in the meantime I came up with a better idea. When I get some time I'm going to work on them some more and see what I can do to build a complete set for testing purposes.... I've got an extra set of KTM 450SX, 04/05 450r, and 89 250R spindles to investigate further as well...

[C41Xracer]

Troy here's some food for thought I'm a machinist and could possibly make the spindles. Has to be done at my pace though. Compliments of my job I can only do side jobs on my lunch breaks and breakfast break.

[troybilt]

Originally posted by C41Xracer
Troy here's some food for thought I'm a machinist and could possibly make the spindles. Has to be done at my pace though. Compliments of my job I can only do side jobs on my lunch breaks and breakfast break.

PM me your email and when I get some time maybe we can work together on some stuff. I'm the same way I don't have much time only evenings to do design work and that is dwindling with the little one. Once she settles down some, I'll have more time for these projects...

[fearlessfred]

Originally posted by troybilt
yea, I have a billet set modeled up, drawn and ready to go, ran into a snafu trying to get a set of them made... so I was sitting on the design for awhile, and in the meantime I came up with a better idea. When I get some time I'm going to work on them some more and see what I can do to build a complete set for testing purposes.... I've got an extra set of KTM 450SX, 04/05 450r, and 89 250R spindles to investigate further as well... i was wandering what people are trying to gain in handling from spindle changes ( travel without balljoint binding,steering radius,strength, weight , braking or appearance ? ) .i remember seeing your design, and i liked it,because it looked trick

[C41Xracer]

my guess would be less bump steer and the obvious easier access to parts.

[fearlessfred]

Originally posted by C41Xracer
my guess would be less bump steer and the obvious easier access to parts. well honda kinda got it correct as it can be for that design and amount of travel . bump steer would more than likly increase by going to another models spindle. unless corrected by placing the outer balljoints back to there orginal height. the way to reduce but not eliminate is by narrowing the frame ( moving the a arm pivot points closer to each other ) or something like what polaris did . i due understand the need for a diff. spindle to gain travel without balljoint binding or weight loss, but changing the spindle to reduce bumper steer on the 250r would be a waste of time and money. troy built would u post a pic of your design again

[troybilt]

Fred, I can send you a pic. I'm afraid if I post a pic it might be considered advertising by the forum gods.... IDK though.... Also, these are a work in progress and I don't want to get into a pissing match with some guys here, cause spindle designs, it seems everyone has there preconceived notions and as I found out they don't always align.. its also difficult to explain, without detailed CAD drawings.

I'm actually designing an entire front end, which includes the aarms, and maybe the stem. There is not much one could do to improve the 250r spindles other than lightening them up... WITHOUT changing the aarms etc... they are all tied together and need to be designed together.

I see alot of guys going for the 450r spindles used with 250r aarms. Although, I think they will work fine, I think one is better off sticking with the 250r spindles..., that is just my opinion, and I know some feel strongly the other way on that! I'm not here to argue that.

At my disposal I have KTM 450SX, 450r, 250r, and Protrax T-Pin, spindles that I've studied in great detail. I've also got a full set of Can Am Ds450 spindles and possibly hubs on the way (hopefully)... I'm in the process of scanning all of them to get them into CAD.

[Langbolt]

Here's something to consider too!

A hybrid of a stock spindle & the Pro-trax heim joints

:devil:

[troybilt]

Originally posted by Langbolt
Here's something to consider too!

A hybrid of a stock spindle & the Pro-trax heim joints

:devil:

I think I saw something like that posted awhile back... pretty clever..

I'm curious to what peoples thoughts are about those yolk style joints with the king pin bearings, etc... like on the protrax... what they perceive or seat of the pants feel as far as advantages...

I'm also interested in why there really hasn't been any developments to spindles (save Can Am), since the Protrax and it never really took off as of late, ...in the MX world, IMO... anyway.

250r guys think its the best thing since sliced bread and I'm wondering why. All I hear is it handles better than anything they
ve ever ridden.. etc.. nothng real quantifiable #'s in terms of engineering and design etc... its not patented that I've found in my searching so someone could copy it basically, but no one really has. I hope to do some testing myself when I get my bike done, I don't have any seat of the pants experience with the protrax just caliper measurement... :D.

[fearlessfred]

Originally posted by Langbolt
Here's something to consider too!

A hybrid of a stock spindle & the Pro-trax heim joints

:devil: this is cool.im guessing this setup allows more travel without binding.

[troybilt]

Originally posted by fearlessfred
this is cool.im guessing this setup allows more travel without binding.

That's a good point, maybe the dude should change his tierods too, they appear to still be balljoints?? IDK

Also is that more travel without binding more important that unsprung weight? Cause it would appeared he increased it some with that concept... in my searches unsprung weight is one of the critical factors for designing suspension... I'm not an expert don't claim to be, just a student...

If we talk MX for a second: Travel

From what I've read on several sites now including this one, for uptravel you set the frame on a 2x4, (i've heard some guys even go lower like an inch...)

Then for down travel they set it up on a 13" box, so what you're left with is basically 11" of travel maybe slightly more, I've heard of pushing that to closer to 12"...

[C41Xracer]

Troy the 2x4 and the 13" box is for measuring compressed and exended length for the shock. The travel would be greater that 11"

[troybilt]

Yeppers, but I also think its the total travel too of your suspension (??) ...(as far as)... how much the aarms go up and down...

I'll attempt another quick sketch... see if I'm thinking about this the wrong way... :D

EDIT: before someone again takes a sketch of mine literally, I realize that the camber changes through the travel and I drew the tires straight, I sure there are a whole host of other problems with the currect sketch but I think it illustrates my point.

[fearlessfred]

we think alike. unsprung weight is very important and i know from experance that to much up travel is a waste (desert sled ) because digging the frame in the ground and getting your feet taken of the pegs is no fun. any gains in travel ,past a point needs to be in droop. for mx 12 inchs seams to be the limit .for the desert or more staite line racing more is better.back to your earler post. i have ridden the tpin setup and was impressed. i applaud u for your efforts to make better spindle. the point i was trying to make early on, was that changing from model to model isnt going to be an improvement,all tho i have been told the 400ex with 250r calipers was the way to go on the a 250r. i dont know this for sure.there is no improving bumpsteer from stock to something else, only the chance of making bump steer worse . now for something designed as a replacement bumpsteer can be kept the same as stock and improvements in unsprung weight,and binding can be had. my whole life i have allways thought of improving what ever tool or toy i was using,so please keep up the good work.