Bit of tc advice

[Cory01]

Hi I was just wondering what the benefit, if any of running a spool front diff in 1/10 4wd is
I've bought a few high end second hand cars in the past and they both had this mod.
Is there a reason for doing this?
Cheers

[sosidge]

A spool makes the car more positive out of the corners and a bit more stable under braking. It also generates a bit of initial understeer and takes away a bit of mid-corner speed.

They also place very heavy loads on the front drivetrain and are unforgiving of crashes - you will break stuff a lot more easily than with a diff.

They are good on medium-to-large tracks in medium-to-high grip. I prefer a tight diff on small tracks and low grip conditions, but I know a lot of people that run a spool in those conditions as well.

[Cory01]

Thanks that's some good info. It's quite a tight track I race at but a few people run spools. I'll see how it goes with the spool befor changing it

[discostu]

all the top drivers run spools i did when i was racing tc tight open flowing spool all the way.

stu rand

[a.wojtecki]

I race indoors on a fairly tight track (18x12 m) and have run all the different front drive options over the years. I started off with a diff, it was easy to drive and gave the car a very neutral feel (almost too neutral for me). Then I used a one-way which was faster but took some time to get used to as it was much more difficult to drive. I continued with the one-way until the power increase that came with the brushless motors made it too difficult and I switched to a spool.
The spool is just as quick but requires a different driving style. As the front axles are locked together there will be a greater tendency to understeer on corner entry but by the same token there will be much better drive on corner exit. It is certainly true that the spool is much harder on the front drive train - you definitely need steel driveshafts as aluminium will either bend / break / wear out far too quickly. The general wear rate on the components is also increased, but not to an unacceptable level.
One option that I've heard that gives similar characteristics to a spool but is a little kinder on the drivetrain is to use a gear diff filled with putty. That way it pretty much locks the front axle but the putty has a small amount of give in it that a conventional spool doesn't. The trade off of course is that it'l have a significantly greater mass than a spool.

[ginge]

I have been told to use a spool. But I can't get one for my car. I tryed to glue a diff but it was out of shape when it dryed. So now I have took out the balls in another one and filled it with blue tack. It feels locked good and tight. But not sure if it will last.

Is their a better way to lock a ball diff ??

[sosidge]

What car are you running?

Fine sandpaper cut to fit the ball-diff plates was used in the past. It grips the diff gear pretty well without damaging the parts should you want to rebuild it as a diff.

Your blu-tack might lose it's stick when it gets hot.

[ginge]

Will try that. Will see how long the blu tack lasts
It a yokomo mr4 tc. Their was one for sale on ebay. But I missed it.