New Kyosho Lazer SB Dirt Cross (4WD Dirt Master-ish)

[BuggyGuy]

I've finally got one of these and completed it this week.

Very nice build, easier than the Dirt Master (a lot less searching for random sized spacers on unlabeled parts trees) - and no self tapping screws either. I did swap out the kit bearings for some Avid branded items though as the bearing quality in the Dirt Master was very low and I didn't want to get caught out again in the same way, the screws Kyosho supply (hex head machine thread) also feel very cheap - so use a good driver and be careful, or get a screw kit from somewhere reputable before started the build.

Took it for a quick blast around the local astroturf track and was quite impressed, with the same electrics and tyres it was quicker than my DB01RRR.

Only really disappointing bit for me was the slipper clutch plates, they are just basically giant unfinished steel washers - but luckily I had some spare DB02 clutch plates that were a direct fit and were much nicer.

Car has a decent setup window - you get lots of suspension blocks in the box for adjusting toe in and stuff, it's not an exact replica of the ZX5 from a geometry POV, as it has a slightly different front hub arrangement - but it's close enough.

I've ordered some CVD driveshafts (needed to improve front steering lock) and some antirollbars and will take it to the next club meeting to see how it fairs against the B74's and XB4's - I think it will be reasonably competitive on any track that's not very high grip. Certainly drives a lot nicer than the TD4 if anyone's looking for a new cheap 4WD club racer.

I ran with a 5.5T motor with the only issue being the wheel hexes looking a bit sad when I checked them after I got home. If you run a hot motor - change them to some aluminium ones at the earliest opportunity.

 

[ChrisRx718]

Good to hear your review @BuggyGuy - my kit turned up yesterday and I'm keen to get started!

I was going to ask whether 8.5T BL would be 'too much' but seeing as you're rocking 5.5T I think I'll be within my comfort zone for speed/power! 

I've also purchased the front CVDs - I was surprised to find the kit didn't already have them, but I guess that's the low entry-cost.

Also noted ref. hex drives - I think I have some Tamiya ones somewhere I can donate to the build. 

[matisse]

nice, the ZX5 was always a super easy to drive chassis, seriously considering one of these as i never should have sold my zx5.

[BuggyGuy]

Been tinkering a bit more, the following bits fit:

- Kyosho ZX7 battery posts (allows fitment of shorty lipo easily in various positions) #LAW80

- Kyosho RF aluminium suspension block fits and can also be used in the RR position #LAW36GM

- If you want an alloy servo horn that fits without trimming the chassis then Associated #AS1364 fits (note that part no. is for 23 tooth spline sevos like KO or Sanwa)

- Any ZX6 or ZX7 anti rollbars, or rear anti rollbars from the RB7 or RB7.5  can be fitted. Use #LA237GM for the stabiliser ends, use #TF270 with the small ball cups included in the kit to attach them to the arms. An 10mm set screw with an M3 nut on top will secure the rollbars to the gearbox top.

- Kyosho clamping hexes from ZX7 #UMW523GMB are a perfect fit and keep the car the right width with the kit wheels or ZX6/7 wheels if you are racing.

Other thing to note is the car (well my car at least) is under the weight limit for racing, I had to put a 30g weight under the lipo to make race weight. Weight distritibuion in the car is odd compared to modern stuff, so put the lipo fully forward and buy a corner weight measure set (or put a wheel on 4 cheap kitchen scales from Amazon) to try and get your left/right balance right.

Realistically you won't be able to balance this car front to back - so bear this in mind when jumping, the rear weight bias is good for low traction tracks, but you race on high grip you'll probably want a more aggressive front tyre than you'd normally run to make up for the rear weight bias.

 

 

[bromogatos309]

On 5/23/2025 at 2:23 AM, BuggyGuy said:

Been tinkering a bit more, the following bits fit:

- Kyosho ZX7 battery posts (allows fitment of shorty lipo easily in various positions) #LAW80

- Kyosho RF aluminium suspension block fits and can also be used in the RR position #LAW36GM

- If you want an alloy servo horn that fits without trimming the chassis then Associated #AS1364 fits (note that part no. is for 23 tooth spline sevos like KO or Sanwa)

- Any ZX6 or ZX7 anti rollbars, or rear anti rollbars from the RB7 or RB7.5  can be fitted. Use #LA237GM for the stabiliser ends, use #TF270 with the small ball cups included in the kit to attach them to the arms. An 10mm set screw with an M3 nut on top will secure the rollbars to the gearbox top.

- Kyosho clamping hexes from ZX7 #UMW523GMB are a perfect fit and keep the car the right width with the kit wheels or ZX6/7 wheels if you are racing.

Other thing to note is the car (well my car at least) is under the weight limit for racing, I had to put a 30g weight under the lipo to make race weight. Weight distritibuion in the car is odd compared to modern stuff, so put the lipo fully forward and buy a corner weight measure set (or put a wheel on 4 cheap kitchen scales from Amazon) to try and get your left/right balance right.

Realistically you won't be able to balance this car front to back - so bear this in mind when jumping, the rear weight bias is good for low traction tracks, but you race on high grip you'll probably want a more aggressive front tyre than you'd normally run to make up for the rear weight bias.

 

 

Is there really anyone who would use the SB for racing? I mean , sure the Lazer zx5 platform is pretty capable, but I was wondering if it can handle AstroTurf tracks with some upgrades like the big bore shocks and the cvds front and rear.

[Howards]

1 hour ago, bromogatos309 said:

Is there really anyone who would use the SB for racing?

Yes - I had a great scrap with a chap racing one of these vs. my TD4 at Stotfold the other week. It's a strong platform. The difference between this era of kit and modern stuff is marginal unless you are a very capable driver (i.e. regional / national contender). 

[RustyHunter]

I’m in the process of building mine and so far been very happy with it. Labeling the sprites would have been nice, but I only found it a problem on bag 6 where it seems almost all the plastic parts are! I labeled them based on pg 11.

My only complaints so far are that the servo saver was a pain to assemble, and turnbuckles aren’t the most fun, but they aren’t any worse than most cars.

What are you guys doing for the body? I’m debating how many of the stickers to use, but definitely leaning towards a bright green and white similar to what Kai City did.

[bromogatos309]

10 hours ago, Howards said:

Yes - I had a great scrap with a chap racing one of these vs. my TD4 at Stotfold the other week. It's a strong platform. The difference between this era of kit and modern stuff is marginal unless you are a very capable driver (i.e. regional / national contender). 

Interesting. Considering the long history I have with the zx5 , I might upgrade mine to make it a proper racer. Who knows ? I might even pick up a new sb

[BuggyGuy]

On 5/24/2025 at 10:20 AM, bromogatos309 said:

Is there really anyone who would use the SB for racing? I mean , sure the Lazer zx5 platform is pretty capable, but I was wondering if it can handle AstroTurf tracks with some upgrades like the big bore shocks and the cvds front and rear.

If your racing on a really high grip surface you would struggle, but most tracks round here are low to medium grip astro so disadvantage of running this car is marginal. 

With a few hopups the setup window on the car is pretty large with lots of roll centre adjustment and all the toe/anti-squat settings you would want.

I won't be racing mine at the regionals (got an XB4 for that) but it's fine for a club meeting as long you have the front driveshafts at minimum.

It would be more sensible/better value for someone new to racing to buy a used XB4/B74/L1R - but I'm really into my Tamiya/Kyosho/Yokomo so run them everywhere I can as long as it's not a super serious meeting like say MKGP, or another regional/national level event.

[BuggyGuy]

22 hours ago, RustyHunter said:

...

What are you guys doing for the body? I’m debating how many of the stickers to use, but definitely leaning towards a bright green and white similar to what Kai City did.

I found some old stock of the Team Azarashi Gomurph and used one for the SB: http://www.team-azarashi.com/page_thumb224.html

Velcro'd it on rather than body clips, I went for a modern race wing as well (JConcepts).

I'll probably get one of these next: https://penguincustombodyshells.co.uk/product/kyosho-style-zx5-bodyshell-vintage-iconic/

I think the kit body would definitely protect the rear shock tower more than either of the above though.

 

[RustyHunter]

1 hour ago, BuggyGuy said:

I found some old stock of the Team Azarashi Gomurph and used one for the SB: http://www.team-azarashi.com/page_thumb224.html

Velcro'd it on rather than body clips, I went for a modern race wing as well (JConcepts).

I'll probably get one of these next: https://penguincustombodyshells.co.uk/product/kyosho-style-zx5-bodyshell-vintage-iconic/

I think the kit body would definitely protect the rear shock tower more than either of the above though.

 

What did you do for paint scheme? Those look more modern and would help camouflage what chassis you’re beating people with!

[BuggyGuy]

1 hour ago, RustyHunter said:

What did you do for paint scheme? Those look more modern and would help camouflage what chassis you’re beating people with!

PS-46 (Iridescent purple/green) with a 2cm stripe round the bottom of the body in PS-7 (orange)

[bromogatos309]

On 5/25/2025 at 1:00 PM, BuggyGuy said:

If your racing on a really high grip surface you would struggle, but most tracks round here are low to medium grip astro so disadvantage of running this car is marginal. 

With a few hopups the setup window on the car is pretty large with lots of roll centre adjustment and all the toe/anti-squat settings you would want.

I won't be racing mine at the regionals (got an XB4 for that) but it's fine for a club meeting as long you have the front driveshafts at minimum.

It would be more sensible/better value for someone new to racing to buy a used XB4/B74/L1R - but I'm really into my Tamiya/Kyosho/Yokomo so run them everywhere I can as long as it's not a super serious meeting like say MKGP, or another regional/national level event.

Unfortunately, here in Greece , the majority of tracks are AstroTurf. Still , considering that it has gear diffs compared to the ball diffs the original zx5 had , I think it's new parts will serve as a great upgrade path of the zx5 and the zx5 sp. 

[RustyHunter]

I've finally had a chance to paint my dirt cross and get a few battery packs through it. Overall, I'm very happy with how it drives! The kit went together pretty well and is my best driving car by far.

I had a few issues with it during my initial test drive, but those weren't really the car's fault. First, I was having issues with losing signal when the car was ~30ft away from me. I'm using a Spektrum SR215 receiver, and I was able to fix this problem by moving the antenna from the stock location behind the servo to where the driver mounts on the top deck. Second, I was having thermal issues, mainly with the ESC (Castle Sidewinder 3). I had slightly overgeared my 4000kV Hobbywing by using the supplied 24t pinion, so I dropped to a 21t pinion for now, although I may go up another tooth as I get more laps in. The field I was running in had a little bit too thick of grass that was also causing a lot of heat issues. When I took it to the loose dirt track, temps were just fine. Just to be safe, I've also got a fan for the ESC on the way, so it should be all sorted soon. The final issue was my mistake. When I swapped the 21t pinion in I must not have tightened the motor quite enough, so the mesh shifted and damaged the spur. I caught it before it became too deformed, but I have a spare spur on the way to swap in at some point. Once I got the Dirt Cross on the track, it was a joy to drive, and I see myself putting a lot of laps in this summer.