1985 vs 1987 250sx

[Doors1024]

Short and quick...

Will a 87' 250sx rear axle fit a 85'?

Thanks,

-Rob

[hillbilly 200x]

I don't think so but I maybe wrong. I know on the 85's the rear brake drum is held in place by the hub and the 86-87 had the drum on its own then a hub on its own. I maybe wrong.

[Doors1024]

...well... I'll find out when it comes in. *face palm*

[PerryS]

Doesnt the 87 model have a sealed carrier. If so you wouldnt have to be as worried about getti.g water in the rearend. I think ive read that somewhere online.

[Tri-Z Pilot]

If you have the opportunity pick up the complete 87sx rear end. They are said to have an awesome gearing setup different from the other sx's

[the great gazoo]

Yes, the 86/87's had the sealed differential, I'm not sure what was different from the '85s, but I had my 87 through some DEEP stuff & it never had issues. The 85, on the other hand, doesn't do well in water AT ALL!! The main problem I have w/ mine is the shoes stay wet & fall off the bakings & the pin that turns the shoes outward gets locked up if I don't clean it & dry it after every water soaking,
Triz-Pilot, I never heard the 2nd gen SX's had different gearing, I've had both & never noticed the difference. Wher'e'd you hear that?

[PerryS]

So will the 87 rearend fit the 85 swinger or will you need the 87 swinger also which driveshaft will you need.

[Tri-Z Pilot]

Well Gazoo whats up man? Haven't seen you since Pennsyltucky 09.
Anyway I think it was on here there was a discussion on this, apparently the 87 sx's had a different final drive making them more 'peppy' or something.

[atc350xer]

So will the 87 rearend fit the 85 swinger or will you need the 87 swinger also which driveshaft will you need.
The differential will swap, but that's it for rear end parts. Totally different designs. The entire swinger assembly will swap over, however... I had a whole '85 swinger on my '87.

[PerryS]

I dont mean to thread jack but how about the 300 fourtrax rearends how does the gearing compare? Do they run a sealed rearend?

[atc500x]

300 fourtrax is a completly different setup

[Tri-Z Pilot]

Which one was the same then? 250 fourtrax? Did they use the sx motor too? I did the research on this years ago and I know one of those rear ends works on the atc250sx/es

[atc500x]

250sx,250es and trx250 use the same differential(different gearing for the es and trx)
250es is a unique design for the swingarm
250sx and trx250 swingarm are very similar,not sure if they interchange
250es 1985 use a specific design for this year,86-87 is different
250sx 1985 use a specific design for this year,86-87 is different
complete rear can be swapped from 85 to 86-87

no parts will interchange with the trx300

[PerryS]

Is the gearing on the trx 250 higher or lower than the 250sx

[atc500x]

lower
the SX gearing is faster but i'm pretty sure anybody can feel the difference
My SX have a 250es gearing and I hit 60 mph.....

[atc350xer]

250sx and trx250 swingarm are very similar,not sure if they interchange


pretty sure the trx swinger is longer, someone on here put one on an sx to have a slightly extended swing arm

[Name Brand]

The 86/87 TRX swinger is three inches longer than the SX swinger. It will bolt right up to the SX frame with the same bearings, but a solution for connecting the bottom of the rear shock is required.

The TRX diff has lower gearing than the SX; it turns 25" tires very well. With a 22" tire it has loads of hill climbing power, but the top speed was painfully slow.

[PerryS]

The sx differential and gears should fit the trx rearend and ai assume you have to you the trx driveshaft as well.

[Doors1024]

UPDATE: a 87' 250SX rear axle will definitely not fit an 85' 250SX. It's a couple inches longer overal and the splines for the rear right are almost twice as long...

Will post pictures comparing the two soon....

***For sale: 87' 250SX rear axle***

[Mint Trike.]

I have heard that 85 sx shaft is weaker an can snap when down shifting on a road ? i dont really believe that it will snap but .,i donno