Pro-Line 1.9" Single Stage Closed Cell Rock Crawling Foam Inserts (2)

Bought these to replace the stock Hyrax 1.9 (Predator compound) on my TRX-4 Sport (3kg, 6.6lb) crawler.

The foams are quite a bit smaller in height to the tire carcass. This however works well as the gap between the hard foams and the tire carcass allows some flex and deflation increasing the contact patch.

Compared to the stock foams (which were too soft) you can expect much better handing. The steering is more precise and controlled even on high speeds or when making a turning descent off a steep incline there is minimal understeer. You can expect better technical line control and recovery with this tire foam combination.

One thing is that the foams has a band that is designed to fit in the groove of a Pro-Line wheel to eliminate lateral movement within the tire. Using a non-Pro-Line wheel may cause some lateral movement of the foams when installed in tires during use with tires with weaker sidewalls. Compared to the Hyrax the Cannon Trails performed much better in this aspect when using the SSD wheels due to sidewall thickness being much more thicker than the Hyrax which holds the foam much more securely (time will tell).

Over the stock you will find the tire sits much taller because there is little compression of the tires with my particular rig weight. This has an effect of raising the CG slightly and causes body angles a little higher at the corners when climbing over obstacles as normally softer foams will allow for the tires to squat a little more at pressure ends of the vehicle. This can cause some changes in the vehicle handling due to the changing CG dynamics making it a little bit more unpredictable.

Works very well with the stock TRX-4 Cannon Trails and is water proof. I would give it 5 stars if the band was removed to make it more suitable for other wheels brands.

I wanted waterproof, durable foams for my heavy TRX-4 running Pro Line M/T Baja Pro X 1.9”s. I wanted waterproofness (so they wouldn’t dissolve and become limp like stock) stiffness (so I wouldn’t be running on flat tires) and better sidehilling performance. I wasn’t sure what to expect since my tires (MT Baja Pros) were not on the compatibility list. I installed them and have been running them for about 2 months now.

They soften about ~10% from new, then hold steady firmness after. At first, I was worried about the stiffness (they felt extremely stiff when I unbagged them) but it was a nonissue. Scalewise it looks like I’m running 10PSI. Technical crawling performance is just fine, but I’d get real foam if you are crawling technical courses. For 98% of regular crawling, these do extremely well. You don’t have to worry about water or mud because they are closed cell.

I would recommend these foams!

I like it for trail heavy rig over 8 pounds makes side hilling more stable

I use these with JConcepts Landmines 1.9” tires for use in water. They will be much stiffer than typical foams, but this would be ideal if your crawler is very heavy. I would not recommend these for a lightweight crawler because the tire will not conform well to rocks. When sidehilling the tires hold their shape and the sidewalls remain stiff.

The 5 star rating is for both the service from Amain Hobbies and the quality of these foams. Proline always makes great products. I recommend these foams for any trail or crawler R/C vehicle.

Very firm and good for heavy trucks but they should be a bit wider too.

They really allow the tire to wrap around the sides abit and gain more traction. It's weird when you first install them because they are so much smaller than a normal foam but they really work well.