When I first got these wheels I was skeptical...I had heard that these wheels were more predictable and grippier then other grip oriented wheels such as Manx and 3dm.
I compared the specs of these wheels:
Grippins Specs (from www.abec11.com)Duros - 75a, 78a, 81a, 84a, 88a, 92a
Height - 70mm
Width - 52mm
Contact Patch - 50.5mm
Hu Size/Type - 25mm/Centerset
Urathane Depth - 22.5mm
Description - Grippins grip like suction cups with their hard-edged hourglass shape plus inner and outer flexible lips. They are very fast, smooth, high traction wheels and provide controlled slides. Narrower than the Gumballs, yet with a wider contact patch than the Gumballs. 75a and 78a are perfect for Buttboarding. 75a, 78a, 81a, 84a are great for carving and cruising. Mix and match 84a, 88a, 92a for tight and hybrid slalom.
3dm Avalon Specs(from www.3dm-sport.com)
Duros - 75a, 78a, 80a, 85a, 90a
Height - 68mm
Width - 55mm
Contact Patch - 54mm?
Hub Size/Type - 28mm/Offset
Urathane Depth - Unknown
Description - Combining supreme speed with amazing traction, the extra mass of these 68mm wheels helps to carry speed through every turn. Offset bearing seat means added grip on outside and inside edges. Named after the famous slalom racing site on Catalina Island, California.
Manx 69 Specs(from www.pocketpistolskates.com)
Duros - 78a, 80a, 84a, 88a
Height - 69mm
Width - 52mm
Contact Patch - 51mm?
Hub Size/Type - ??/Offset
Urathane Depth - Unknown
Description - Unknown
As you can see all the wheels are pretty similar. The only big difference in all of them is that the Grippins are center-set. I have personally ridden 3dm Avalons in 74a and they had very good traction and good speed. My Grippins are in 75a and were slipping in some carves. They did not have have much grip as Avalons in the first 30 minutes I was riding HOWEVER after about 30 minutes the slippery outer layer of the wheel started to wear off and I noticed a significant increase in grip. These wheels are FAST for being 75a. I would say they are significantly faster then the Avalons. I have never ridden the Manx so I can not give a good comparison.
Spacers are usually an issue with some of my wheels...I previously had these spacers in Flashbacks and Flywheels and they didn't quite fit right in either of them. When I put them in the Grippins I could tighten the nut down until it stopped and they still spun perfectly. I tested these wheels on various different surfaces and they do slip on bumpy pavement but it is a very predictable slide that grips right back up. The same was true for smooth pavemtn except they gripped up much faster. I heard about them gripping up before I got them and was kind of nervous about it. It does NOT throw you off like I thought it would. Whenever I was ridign onn the Avalons whenever they slipped they were gone...
I took these wheels on two downhill runs and they were surprisingly fast. Just as fast as my Flashbacks in 81a.
The Verdict:
Speed: 9
Grip:9
Predictability:19
Wear:10
I am very glad I bought these wheels and I have a feeling I will be riding them for years to come.