A new-to-me mountain bike arrives in the next few days: it employs 180fr/160r XTR rotors and levers and two piston calipers. My current bike employs XT four piston calipers with 180 fr/rear rotors.
Question: can I expect the XTR to provide greater braking because of its tier level, or am I better served by swapping the 4 piston brakes/levers/rotors over to the new bike.
I’m inclined to believe that 4 piston 180s will work best, but this is new territory.
What would you all do? What would you all recommend?
I would be very surpised if the two piston XTRs provide more power than the four piston XTs. Though if your XT brakes are a model or two back from current, it’s not impossible that the XTR brakes get realtively close.
With the rear, the smaller rotor size will impact heat build up more than power, as the 2-pot with 160 will still lock you wheel up with little effort.
If they don’t provide adequate stopping power, or you experience greater and problematic heat build up, particularly with the rear brack, then whether you need to switch them out or just up the rotor size is a sensible question to ask.
I recently switched to 4-pot SLX from 2-pot SLX, with the same rotors, and the 4-pots are so much better, but that’s with the same decade+ old levers. From what I understand the newer (although not that new now) levers that have the clamp inboard and an extra support stub are an improvement in and of themselves, regardless of what caliper is used.
My experience is with an older generation, but I found that XT provided more braking power than XTR, with the sacrifice being some weight. Further, the XT seals were better and thus the brakes didn’t need to be bled as frequently. Hopefully this issue is long since fixed.
Anyway, a lot of words to say “don’t assume XTR is better than XT just because of the price”
The 4 piston brakes will stop you better. The one thing to check before swapping them out is which model year the new brakes are. If they are the newer 9200 models, they use a lower viscosity fluid than the older models and the housing is not compatible between the older and newer versions. Just make sure you swap housing as well. Newer bikes with headset routing make it more difficult to do.
JC, thanks for the insight. I had switched my 8 year old Pivot from two piston XT to four piston XT and upped the rotor size to good effect. The arriving bike will have 9100s, so the XTs and XTRs will share fluids.
Quite a few of the 9200 series brakes come with mixed lever/caliper setups. If the levers are the 9220 versions with the hose that closely follows the handlebar, then I suggest you try them out with the 2 piston calipers before automatically switching. This is especially true if you like the lever feel of more power, but you don’t necessarily require heavy brake use. More pistons does not automatically mean more power, but the pads for the 4 piston calipers are longer, and that’s especially true vs the XTR 2 piston calipers in particular. XTR uses the tiny pads from their road brakes on their 2 piston calipers.