Precision Tooling is a family owned machine business that has machined parts from metal for different companies over time. For a period they were the sub-contracting firm making CQP cranks. The relationship with CQP faded and John Trenerry and his father Phil worked out an exciting and stylish design for a crank arm set. Phil's knowledge of metals helped make the arms strong though they appeared delicate. There was initial un-certainty about whether the family should be bold enough to enter the bicycle parts market on their own, under their own name. As it turns out Phil Trenerry had known John Grafton for many years and Grafton's first cantilever brake had been successful. Grafton had been prevailed by others make an entrance in the crank market and the Trenerry's crank held promise though they again were reluctant. The Trenerrys agreed to make the crank they had designed and let Grafton market them. The crankset's popularity and the Grafton name identification lead to immediate market interest. After about a years time we started to be sold the cranks directly from Topline, (which is also known as Precision Tooling), because their verbal contract with Grafton had crumbled. The design remained rightly in the Trenerry hands and they have become very successful using their own name in marketing their own cranks. We've found that generally when splits like this occur, there is usually a problem related to sub- contractors being paid for their work. Have you noticed how similar the Sims cranks are to the last version of Grafton cranks? It's not a well kept secret that Sims was the sub-contractor used to make Grafton cranks after Precision Tooling (Topline)/Grafton relationship ended.
Topline makes a variation of their Mountain cranks with the spider milled out around the 35.5mm large ball. Remember the back side of the spider on the standard ATB drive arm (called "Heavy Duty" by Topline) is already milled to reduce the spider thickness from 6.297mm to 4.480mm, the SLS model has the mill work performed on the front side and in this case, cuts the material away altogether. The weight of a 180mm standard (Heavy Duty) right arm is 246.6 grams, while the weight of the an SLS version of the 180mm arm is 214 grams. These cranks again use the 74mm and 110mm bolt pattern. The cranks come anodized in Black, Blue, Pewter Grey, Lavender, Silver, or High Polished un- anodized silver. We stock them in 170mm, 172.5mm, 175mm, 177.5mm, or 180mm lengths. On a special order basis we can order the cranks anodized in Gold, Green or Red, and we can also special order any of the colors mentioned in a 165mm or 167.5mm length if needed. We found the SLS cranks had a Bike- Pro Q measurement of 149mm. The Topline SLS cranks have a Bike- Pro Q measurement of 149mm. Top Line SLS Mountain cranks come as right arm, with spider, left arm and a set of five steel inner chainring bolts with aluminum spacers. Chainrings, the double chainring bolt set, crank arm bolts, and crank arm dust caps will be needed separately. The weight of the 175mm long SLS crankset with spacer and bolts is 388 grams. The inner bolt and spacer set provided weighs 33.5 grams.
Size-165-167-170-172-175-177-180 Color-B-BK-G-GN-GY-HP-L-R-S $ Price in Catalog
Topline Micro D Mountain Crank Arm Set
