JRX Pro SE runner build

The place for all things Losi.

Moderators: scr8p, klavy69

User avatar
DerbyDan
Approved Member
Posts: 1836
Joined: Tue Sep 08, 2009 8:04 am
Location: Northampton UK
Has thanked: 2 times
Been thanked: 17 times

Re: JRX Pro SE runner build

Post by DerbyDan »

My next 2wd runner/racer project is also a JRX Pro SE (been saving up parts for a little while), so i'm following this build thread closely..... & taking notes!

Your car looks immaculate (like new) - I'm looking forward to hearing how it performs on track!

I've run my LRM gearboxed JRX2 with an 8.5 brushless set-up - which has proved reliable with the addition of a slipper & some Thorpe gears - but like you, I'm planning on going XX Retrofit for my build to be doubly sure on reliability.... & I would like to go hotter on the motor for the Pro SE. Out of interest - do you know if the standard length XX driveshafts can be used for the Pro SE that is equipped with a Retrofit transmission?

Splat!
Approved Member
Posts: 35
Joined: Thu Apr 11, 2013 11:40 pm
Location: Ann Arbor, MI

Re: JRX Pro SE runner build

Post by Splat! »

Thanks for the info on the wheel setup!

I just got a set of those Jrx2 towers yesterday- SO nice! The carbon weave is really fine, never seen anything like it. The towers are easily double the thickness of the stock so should be way stiffer.

Wonder if that guy will ever make chassis plates :shock: :shock: :shock: !
TEAM LOSI/TRINITY
SPLAT! GRAPHICS

sixdub
Approved Member
Posts: 134
Joined: Fri Jan 19, 2007 12:30 pm
Location: Senoia Georgia
Has thanked: 4 times
Been thanked: 54 times

Re: JRX Pro SE runner build

Post by sixdub »

DerbyDan wrote: Fri Mar 03, 2017 11:18 am Out of interest - do you know if the standard length XX driveshafts can be used for the Pro SE that is equipped with a Retrofit transmission?
Sorry for the delay, I've been ill for over a week. :(
Getting back in the saddle now.

I'm not sure if the XX dogbones will work or not. If you have some you can measure, I can compare to my retrofit bones.
Splat! wrote: Fri Mar 10, 2017 3:11 pm Thanks for the info on the wheel setup!

I just got a set of those Jrx2 towers yesterday- SO nice! The carbon weave is really fine, never seen anything like it. The towers are easily double the thickness of the stock so should be way stiffer.
Now you are going to make me spend more money on this "low cost" project. :twisted:
Kyosho, JRX-2, Gold Tub Fan

sixdub
Approved Member
Posts: 134
Joined: Fri Jan 19, 2007 12:30 pm
Location: Senoia Georgia
Has thanked: 4 times
Been thanked: 54 times

Re: JRX Pro SE runner build

Post by sixdub »

Got a few minutes to work on the buggy today. It's obvious I will have to deal with the front droop/shock length.

Image

I mounted a XXX v-wing using xxx4 mounts attached to the rear tower. I screwed up the hole layout, so I'll have to replace the tower and correct the layout. A good excuse to order the carbon towers from Ebay...

Image

Image

Image
Kyosho, JRX-2, Gold Tub Fan

sixdub
Approved Member
Posts: 134
Joined: Fri Jan 19, 2007 12:30 pm
Location: Senoia Georgia
Has thanked: 4 times
Been thanked: 54 times

Re: JRX Pro SE runner build

Post by sixdub »

DerbyDan - I measured the retrofit dogbone pin to pin. Approx. 61.7mm.

Image

Corrected the front droop with 5mm of internal limiters.

Image

Getting the front track width correct (~250mm) with the B4 wheels was a little tricky. I started with Losi GTX front axles A-1022, but that ended up being too wide. As I don't have access to a lathe to reduce the shoulder length on the GTX axles, I decided to shorten the axles on the kingpin side and drill new kingpin holes. This allowed the width to be just under 250mm and I made up the difference with shims on each side.

Image

Image

The 10-32 axle nuts won't fit on the recess of the B4 wheel, so I am on the hunt for some small pattern lock nuts. In the interim, I'm using an axle spacer between the outer bearing and axle nut.

Image

The rear width is perfect with the addition of some Custom Works .125" spacers.

Image

Image
Kyosho, JRX-2, Gold Tub Fan

User avatar
LosiXXkid
Approved Member
Posts: 757
Joined: Sun Mar 03, 2013 5:35 pm
Location: Islington, North London
Has thanked: 2 times
Been thanked: 6 times

Re: JRX Pro SE runner build

Post by LosiXXkid »

Splat! wrote: Fri Mar 10, 2017 3:11 pm Thanks for the info on the wheel setup!

I just got a set of those Jrx2 towers yesterday- SO nice! The carbon weave is really fine, never seen anything like it. The towers are easily double the thickness of the stock so should be way stiffer.

Wonder if that guy will ever make chassis plates :shock: :shock: :shock: !
Well, I guess there's only one way to find out............, and a quick email should do the trick!
~I'm a lot older now than I was then and wish that I knew then what I know now~

User avatar
LosiXXkid
Approved Member
Posts: 757
Joined: Sun Mar 03, 2013 5:35 pm
Location: Islington, North London
Has thanked: 2 times
Been thanked: 6 times

Re: JRX Pro SE runner build

Post by LosiXXkid »

LosiXXkid wrote: Sun Mar 12, 2017 7:53 pm
Splat! wrote: Fri Mar 10, 2017 3:11 pm Thanks for the info on the wheel setup!

I just got a set of those Jrx2 towers yesterday- SO nice! The carbon weave is really fine, never seen anything like it. The towers are easily double the thickness of the stock so should be way stiffer.

Wonder if that guy will ever make chassis plates :shock: :shock: :shock: !
Well, I guess there's only one way to find out............, and a quick email should do the trick!
Email sent.

Awaiting response.
~I'm a lot older now than I was then and wish that I knew then what I know now~

User avatar
matt1ptkn
Approved Member
Posts: 910
Joined: Wed Dec 12, 2012 8:27 am
Location: Moundsville, WV
Has thanked: 80 times
Been thanked: 132 times

Re: JRX Pro SE runner build

Post by matt1ptkn »

I was going through my Losi parts this weekend, organizing. The XX and XX Retro Fit Transmission dogbones are the same. They even use the same part numbers (A-3081). Only difference is that one says XX dogbone and yoke while the other indicates XX retro fit trans dogbone and yoke.

Something else I noticed recently, my retro fit trans came with short drive cups. There is just enough meat for the dogbones to engage. I have several other sets of outdrives for the XX, and they are all slightly longer, maybe by 1-2mm. Anyone else ever notice this and are there different part numbers for different length XX/retro fit trans outdrives?
Matt

Just a part of my RC collection: Matt1ptkn's Toys

"I wish there was a way to tell you're in the good old days, before you've actually left them."

sixdub
Approved Member
Posts: 134
Joined: Fri Jan 19, 2007 12:30 pm
Location: Senoia Georgia
Has thanked: 4 times
Been thanked: 54 times

Re: JRX Pro SE runner build

Post by sixdub »

matt1ptkn wrote: Mon Mar 13, 2017 8:20 am I was going through my Losi parts this weekend, organizing. The XX and XX Retro Fit Transmission dogbones are the same.
Good to know, thanks! 8)
matt1ptkn wrote: Mon Mar 13, 2017 8:20 am Anyone else ever notice this and are there different part numbers for different length XX/retro fit trans outdrives?
Maybe you have a some xxx-nt "monster diff" outdrives A-2905/A-2906? They look very similar to the xx outdrives. Does the diff have the separate aluminum center male part or is the male part machined in one outdrive?
Kyosho, JRX-2, Gold Tub Fan

User avatar
matt1ptkn
Approved Member
Posts: 910
Joined: Wed Dec 12, 2012 8:27 am
Location: Moundsville, WV
Has thanked: 80 times
Been thanked: 132 times

Re: JRX Pro SE runner build

Post by matt1ptkn »

My XX retro fit transmission diff outdrives do not have the male piece attached. There is the separate aluminum piece that fits in with the diff screw assembly. I therefore assume that means that someone swapped in some XXX pieces? I roughly compared the outdrives in my XX retro trans to my XXXT outdrives, and they do look very similar, if not the same. At least I have some of the proper outdrives on hand. Which leads me to a question: I have the metal dogbone outdrives as well as the molded plastic outdrives for the plastic sliders. Which is better between metal dogbones and plastic sliders?
Matt

Just a part of my RC collection: Matt1ptkn's Toys

"I wish there was a way to tell you're in the good old days, before you've actually left them."

sixdub
Approved Member
Posts: 134
Joined: Fri Jan 19, 2007 12:30 pm
Location: Senoia Georgia
Has thanked: 4 times
Been thanked: 54 times

Re: JRX Pro SE runner build

Post by sixdub »

The aluminum center (A-3072) is correct for the XX retro trans. The dogbone outdrives are A-3073.

In my opinion, dogbones are the better choice for brushless power.
Kyosho, JRX-2, Gold Tub Fan

sixdub
Approved Member
Posts: 134
Joined: Fri Jan 19, 2007 12:30 pm
Location: Senoia Georgia
Has thanked: 4 times
Been thanked: 54 times

Re: JRX Pro SE runner build

Post by sixdub »

Woot! :mrgreen:

Image
Kyosho, JRX-2, Gold Tub Fan

User avatar
DerbyDan
Approved Member
Posts: 1836
Joined: Tue Sep 08, 2009 8:04 am
Location: Northampton UK
Has thanked: 2 times
Been thanked: 17 times

Re: JRX Pro SE runner build

Post by DerbyDan »

sixdub wrote: Sun Mar 12, 2017 6:37 pm DerbyDan - I measured the retrofit dogbone pin to pin. Approx. 61.7mm.

Image
Thanks for measuring those for for me - so it would appear that the XX dogbones are the correct/same length - that's good to know since I have a fair few of those I can use - as well as a slider set-up if I prefered 8)

Your JRX Pro SE build is coming along very nicely - Its going to soak up the bumps great with those big bore TLR shocks fitted! BTW I found a decent amount of droop to be beneficial in maintaining stability when landing off jumps with my JRX2.... but maybe not quite the amount that you had when you first fitted your TLR shocks! :shock:

sixdub
Approved Member
Posts: 134
Joined: Fri Jan 19, 2007 12:30 pm
Location: Senoia Georgia
Has thanked: 4 times
Been thanked: 54 times

Re: JRX Pro SE runner build

Post by sixdub »

DerbyDan wrote: Thu Mar 16, 2017 6:32 am
Thanks for measuring those for for me - so it would appear that the XX dogbones are the correct/same length - that's good to know since I have a fair few of those I can use - as well as a slider set-up if I prefered 8)

Your JRX Pro SE build is coming along very nicely - Its going to soak up the bumps great with those big bore TLR shocks fitted! BTW I found a decent amount of droop to be beneficial in maintaining stability when landing off jumps with my JRX2.... but maybe not quite the amount that you had when you first fitted your TLR shocks! :shock:
Glad to help!
I hope she runs well when I take her to the track in a few weeks.

I started swapping in Todd's (Vintage RC) carbon towers today. Couldn't work long, just got the old front tower removed.

Image

Image
Kyosho, JRX-2, Gold Tub Fan

User avatar
LosiXXkid
Approved Member
Posts: 757
Joined: Sun Mar 03, 2013 5:35 pm
Location: Islington, North London
Has thanked: 2 times
Been thanked: 6 times

Re: JRX Pro SE runner build

Post by LosiXXkid »

sixdub wrote: Sun Mar 19, 2017 7:22 pm
DerbyDan wrote: Thu Mar 16, 2017 6:32 am
Thanks for measuring those for for me - so it would appear that the XX dogbones are the correct/same length - that's good to know since I have a fair few of those I can use - as well as a slider set-up if I prefered 8)

Your JRX Pro SE build is coming along very nicely - Its going to soak up the bumps great with those big bore TLR shocks fitted! BTW I found a decent amount of droop to be beneficial in maintaining stability when landing off jumps with my JRX2.... but maybe not quite the amount that you had when you first fitted your TLR shocks! :shock:
Glad to help!
I hope she runs well when I take her to the track in a few weeks.

I started swapping in Todd's (Vintage RC) carbon towers today. Couldn't work long, just got the old front tower removed.

Image

Image
My new JRX-2 CF towers are great! :wink:
~I'm a lot older now than I was then and wish that I knew then what I know now~

Post Reply

Create an account or sign in to join the discussion

You need to be a member in order to post a reply

Create an account

Not a member? register to join our community
Members can start their own topics & subscribe to topics
It’s free and only takes a minute

Register

Sign in

  • Similar Topics
    Replies
    Views
    Last post
  • Jrx-Pro Runner
    by sgirouard » » in Losi Forum
    2 Replies
    889 Views
    Last post by sgirouard
  • Notme's JRX Pro runner
    by notme » » in Losi Forum
    14 Replies
    2265 Views
    Last post by notme
  • My JRX-Pro period runner.
    by 8rad » » in Losi Forum
    16 Replies
    1892 Views
    Last post by Bormac
  • JRX PRO - Basket case to restored runner.
    by RETRO R/C » » in Losi Forum
    12 Replies
    2260 Views
    Last post by Camshaft
  • JRX Pro ebay find, runner rebuild
    by RogueIV » » in Losi Forum
    12 Replies
    1682 Views
    Last post by RogueIV
  • New Build JRX Pro
    by Konich » » in Losi Forum
    9 Replies
    765 Views
    Last post by CobraKen
  • Another jrx-pro build
    by aconsola » » in Losi Forum
    4 Replies
    486 Views
    Last post by bearrickster
  • Losi JRX Pro Build
    by Lavigna » » in Losi Forum
    62 Replies
    9379 Views
    Last post by Lavigna

Return to “Losi Forum”

Who is online

Users browsing this forum: No registered users and 22 guests