John Deere 108 "SRT 24" [2016 Build-Off Entry]

2016 ATLTF Build-Off Project 1982 John Deere 108 "SRT 24" This will be a speed mower

24ci Horizontal shaft Briggs ungoverned with Mikuni VM 22
Carlisle Turf tires 18x8-8 Rear 15x6-6 Front
Under carriage exit exhaust
New paint job Black and Yellow
Pull start
Custom intake with Spectre Filter
Live axle rear end
Hydraulic disc brakes
Hand throttle and brake controls

Cool build man I hope it works out for u and every one has a chance of winning

tscustoms wrote:

Cool build man I hope it works out for u and every one has a chance of winning

Thanks man

I think i placed 4th(I think?) in the build off last year and the only new bits I forked out for were cheap $10-12 or less. My tip is to tell lots of people what you are doing (Get parents to tell their friends) you may find people are willing to give bits to you for little or nothing. I've been offered a ride on mower by my local vicars husband (I've not collected it yet due to space issues) and 18 months ago was offered an mtd with a rusty deck for free (I gave them some cookies!). I've never paid more than $80 odd for a mower, usually less. Put an advert on Craigs list or similar explaining what you are doing asking for donations of parts. You may be surprised!

All the best for the build.

Nice! Building a custom front axle?

MatthewD wrote:

Nice! Building a custom front axle?

I'm not planning on building a custom front axle, but i'm planning on locking the front tilt axle without welding it so if i want to change it in the future i can. How i'm gonna do this, i'm not sure but i'll figure it out

All depends on the speed your planning on going. The problem with stock lawnmower axles is that they have some positive camber, which means the bottom of the tyres will be the closest together. This means that at speed, your mower will go into a speed wobble which can be very dangerous. I know this with my Westwood which does 22mph and you have to hold the steering wheel tight or it will wobble about all over the show on you.

You can read this and see. Also a bit on direct steering aswell
https://www.atltf.com/t1773-direct-steering-caster-camber-toe-reference?highlight=caster+++camber

MatthewD wrote:

All depends on the speed your planning on going. The problem with stock lawnmower axles is that they have some positive camber, which means the bottom of the tyres will be the closest together. This means that at speed, your mower will go into a speed wobble which can be very dangerous. I know this with my Westwood which does 22mph and you have to hold the steering wheel tight or it will wobble about all over the show on you.

You can read this and see. Also a bit on direct steering aswell
https://www.atltf.com/t1773-direct-steering-caster-camber-toe-reference?highlight=caster+++camber

oh alright i'm planning on doing 30+mph and trust me i always hold on to the steering wheel for dear life but i'm also undersizing the tires by 4 inches in the front and 5in in the back but i don't know how much that will help the steering control, but thanks for the advice

Hmm yeah. See what the experts think...

Negative camber is defo what you want, but I would do some research/find out from mower racers as to the best steering geometry. I set my hot rod tractor (the red MTD) steering in a rather unscientific way. I de-cambered it until it looked cool, which I think it does! Even with the negative camber, the rest of the steering is pretty much standard lawn tractor. I took it out on a quiet tarmac road near me once and I'd guess I had it up to 25+ mph and the steering was pretty 'gnarley'. I didn't have a helmet on or any 'support crew' with me at the time so backed off as I didn't want my obituary to include 'lawn mower accident'!

marmower wrote:

MatthewD wrote:

All depends on the speed your planning on going. The problem with stock lawnmower axles is that they have some positive camber, which means the bottom of the tyres will be the closest together. This means that at speed, your mower will go into a speed wobble which can be very dangerous. I know this with my Westwood which does 22mph and you have to hold the steering wheel tight or it will wobble about all over the show on you.

You can read this and see. Also a bit on direct steering aswell
https://www.atltf.com/t1773-direct-steering-caster-camber-toe-reference?highlight=caster+++camber

oh alright i'm planning on doing 30+mph and trust me i always hold on to the steering wheel for dear life but i'm also undersizing the tires by 4 inches in the front and 5in in the back but i don't know how much that will help the steering control, but thanks for the advice

Nice tractor to start off with man Those things are pretty rare over here!  The smaller wheels will lower the tractor, which has handling benefits for sure for a drift machine, but the issues with a stock front axle at speed are a combination of different matters as such.  Of course I'm sure that there is people on here that know this axle personally and can better advise but as Matthew says tractors generally, (even the big ones), run a positive camber setup which is naturally unstable and so less suited for drift and speed applications.

Have you seen the drift trikes that have the plastic sleeves slipped on over their rear tyres? guys use these to drastically lower the speed at which the rear of the vehicle will loose traction, you would need to lock the diff tho.  Anyways theres plenty of people on here to help answer questions, theres a way of making it work - and a drift machine is super fun

STUNTMAN JON wrote:

marmower wrote:

MatthewD wrote:

All depends on the speed your planning on going. The problem with stock lawnmower axles is that they have some positive camber, which means the bottom of the tyres will be the closest together. This means that at speed, your mower will go into a speed wobble which can be very dangerous. I know this with my Westwood which does 22mph and you have to hold the steering wheel tight or it will wobble about all over the show on you.

You can read this and see. Also a bit on direct steering aswell
https://www.atltf.com/t1773-direct-steering-caster-camber-toe-reference?highlight=caster+++camber

oh alright i'm planning on doing 30+mph and trust me i always hold on to the steering wheel for dear life but i'm also undersizing the tires by 4 inches in the front and 5in in the back but i don't know how much that will help the steering control, but thanks for the advice

Nice tractor to start off with man Those things are pretty rare over here!  The smaller wheels will lower the tractor, which has handling benefits for sure for a drift machine, but the issues with a stock front axle at speed are a combination of different matters as such.  Of course I'm sure that there is people on here that know this axle personally and can better advise but as Matthew says tractors generally, (even the big ones), run a positive camber setup which is naturally unstable and so less suited for drift and speed applications.

Have you seen the drift trikes that have the plastic sleeves slipped on over their rear tyres? guys use these to drastically lower the speed at which the rear of the vehicle will loose traction, you would need to lock the diff tho.  Anyways theres plenty of people on here to help answer questions, theres a way of making it work - and a drift machine is super fun

As far as locking the transaxle goes I may not be able to do it because I don't have a welder and for drifting I don't necessarily mean drifting on cement so I'm not gonna need the tire boots for the rear end. Also when the tractor still had all tires It didn't show any camber on the front end but I'll check again once I get new tires for it

Not sure how I managed to get my text in amongst the quote there?!

Makes sense jonnya +1, i get where you are coming from re encouraging younger builders for sure

MarMower - doc sprocket did come up with a solution for locking diffs that requires no welder if you can find the parts - it is on his youtube, who knows though - by november you could be a welding supremo!

STUNTMAN JON wrote:

Makes sense jonnya +1, i get where you are coming from re encouraging younger builders for sure

MarMower - doc sprocket did come up with a solution for locking diffs that requires no welder if you can find the parts - it is on his youtube, who knows though - by november you could be a welding supremo!

Cool I'll look into the locker but when I read this I got an idea for a weld less locker that might just work

Woah just seen I'm 3 days older than you! I'd suggest locked diff for drifting, but for speed maybe not so much because it would wear your tyres out and be difficult to steer. Especially with those small front tires.

marmower wrote:

STUNTMAN JON wrote:

Makes sense jonnya +1, i get where you are coming from re encouraging younger builders for sure

MarMower - doc sprocket did come up with a solution for locking diffs that requires no welder if you can find the parts - it is on his youtube, who knows though - by november you could be a welding supremo!

Cool I'll look into the locker but when I read this I got an idea for a weld less locker that might just work

see necessity IS the mother of invention i was 28 when i got my first welder so for 28 years i had to work out how to do stuff without one, it gets you thinking for sure

Update #1: i got the mower the rest of the way apart. and i noticed after i took it apart it has a two pulley clutch system which is good for me so now i dont have to build one, but on the other hand the way the front tilt axle mounts really limit my space where the main engine pulley goes so the biggest pulley i will be able to fit will only be 5-6 inches which i hope is enough but anyways here are some pics





Also i have a bunch of extra transaxle parts like the main shafts and all the gears

to lock that front axle, you can pop a couple holes in the plate of the frame (ahead of where the engine mounts) directly above the axle and drop bolts in.  Get a couple bolts in with locking nuts on both the top side and bottom.   You'll need one to come down on each side of the pivot.

Bonus is that it's easily reversible, adjustable, and a 5-10 minute job.  


Look up kingpin angle and caster angle on front suspension.  primarily kingpin angle and the affect it has, that's what you're fighting against with this and most stock front axles in garden tractors.  


This also causes positive camber when turning, which is bad for cornering grip, but makes the steering want to self-center (let go of the steering wheel in a turn and it snaps straight.  kingpin angle does make the tractor more stable in a straight line.

Bad pic but here is a shot of my front axle ends on my racing mower. I believe they are 10 degree angle? cant remember. but the camber an toe and all is not set. But they are adjustable.

ive hit speeds over 30mph with stock tires and no problems, but if your going to be going that fast dont cheap out on your brakes, plus thats in the rules only im allowed to run no brakes, when i get around to it ill be building a drift/speed mower this year. good luck !

Update 2: I got the mower prepared to be painted and had to wait because it was still 30 degrees outside when I got it prepared but yesterday hit 60 degrees so I got the mower painted black now I need to get my yellow paint for the racing strip on the hood. Also since yesterday was such a nice day I went to the junkyard just to look for stuff I might need for this build and I found my ideal transaxle for this project, a peerless 820 that after 2 hours I finally got the input pulley off. I still haven't completely figured out the front axle situation but I think I have the main idea ready just needs some more thought to it.
Anyways here's some pics.

Update 3: I got my hood the rest of the way painted with a single yellow strip, also I got the peerless 820 apart, cleaned and swapped to oil filled rather than grease filled and got it mounted to the frame and connected to the shifter. Another thing, I wont be able to fit an opposed twin in the tractor because it would hit the hood and the hood would have to be raised 4 inches for it to fit and it wouldn't look nice, so as of now I'm gonna try to find a nice single cylinder engine to fit under the hood, any recommendations on a good vertical shaft single that could possibly be run ungoverned without to many modifications? I'll put up some pics later this week

Id personally go for a briggs L-head, or more commonly known as a flathead. They are dependable, cheap to replace and for the most part respond to mods really well. I dont know how big they get, but the biggest flathead single I've seen so far is a 13hp. Good luck on your search for a motor!