21 January 2024

Fresh Goods Sunday - Shimano XT M8120 Disc Brakes - 4 Piston

 


Last year I bought a new hardtail e mtb to replace my old cube e hardtail mtb. It was a Trek Marlin+ with the new Bosch motor, battery and display. The groupset is Shimano with a mixed bag of groupset parts levels. The brakes were Shimano MT4100 lever with MT420 4 pot calliper and Shimano RT64 203mm disc rotors, not bad for a £3k rrp e bike. I know it takes a while to bed new disc brake pads / rotors in but after a good few rides I was not getting the braking power / feel that I was used to with Shimano brakes on my other mtbs and road/gravel bikes. I swapped out the discs which I will cover in next weeks Fresh Goods Sunday and that improved things massively. I was going to leave the brakes now but a pair of Shimano XT 4 pots come up on Wiggle /CRC sale and thought what the hell, could not turn them down with 43% off. I have the same brakes on my Trek hardtail but in the xc 2 pot version and they re brilliant for the type of riding I do. 
They arrived within a couple of days and were proper boxed ones which I was not expecting and as ever the quality and finish looked spot on. I fitted the front one first as it was the easier one as I did not have to remove the lever for threading the hose through any holes/guides etc. 
The rear was a different kettle of fish! I removed the access covers around the bb/motor area and there was a nest of cables/hoses etc. I used my Park Tool fishing line and scrwed it into the end of the existing hose after I removed the lever to pull it down the down tube, around the motor and out through the rear chain stay. I then unscrewed the guide wire and screwed it into the end of the new hose and gentle pulled it back through the rear stay, around the motor then the hardest part was up the down tube around the battery. It got stuck a few times but managed to get to pulled through all the way and out and up to the handle bars, thank the lords! I then used screwed the guide cable, adjusted the hose length to suit and fitted a new end and screwed it back into the lever. I bleed the brake to get out a very small amount of air and fitted the remote fork lockout to the underside of the lever. I centred the callipers against the rotors and set the angel of the levers and that was job done. I did not adjust the amount of reach on the lever blade as it was spot on from the box. After a few rides I did not have to re centre the calipers, there was no rotor rub and no fade in the lever so no more bleeding. 
My brake feel was back again that I was used to and the extra braking power from the 4 pot calipers defo comes in handy now and then on longer, faster and steeper descents with the extra weight of the e bike. They come with finned pads so I did not need to swap them out and will probably last me a long time as I dont do mega miles on the bike. 
If it was not for the massive discount I would have not upgraded to XT for £200rrp per end but as ever shop around in this quiet market. They are defo 100% worth the money I paid for them and will not be swapped now again until I sell the bike in many years to come. 

RRP £399.98 and I paid £226.32 from CRC inc 48hr p&p. Discount 43% 

Manufactures Blurb - 

SHIMANO DEORE XT - Hydraulic Disc Brake Lever - I-SPEC EV Clamp Band

With a focus on reduced weight and cross-country tuned stopping power, the SHIMANO DEORE XT BL-M8100 lever provides intuitive modulation so that you can explore your limits with confidence.


FEATURES

  • Intuitive and versatile braking keeps your focus on the trail
  • Optimized lever axle position with additional contact point and refined ergonomics
  • Greater flexibility and action-optimized cockpit layout
  • I-SPEC EV
  • High rigidity
  • 10% stiffer than M8000 even under high temp conditions
  • Quicker brake engagement with shorter free stroke
  • Rider tuned adjustment
  • Toolless reach adjust
  • Free stroke adjust

MODEL NO

BL-M8100

SERIES

DEORE XT M8100 Series

Color

Series color

Average weight

105

Brake typeHydraulic disc brake
Lever size (finger)2
Brake hose (kit)SM-BH90-SBM
Hose jointStraight
Brake hose color (kit)|1Black
J-Kit spec (for OEM)
SERVO WAVE
Reach adjust|Toolless
Free stroke adjust
Compatible shift lever mount|Clamp band
Compatible shift lever mount|I-SPEC EV
Clamp band|Open clamp
Shift lever rotation angle adjust range (I-SPEC EV ; deg.)20
Recommended brake caliperBR-M8100, BR-M8110-R, BR-M8120
OilSHIMANO mineral
Funnel bleeding


SHIMANO DEORE XT Hydraulic Disc Brake 4-Piston Caliper

BR-M8120

SHIMANO DEORE XT - 4-Piston - ICE TECHNOLOGIES - Hydraulic Disc Brake Caliper

The SHIMANO DEORE XT M8120 caliper features consistent braking performance and reliable stopping power in all conditions. The 4-piston caliper instills greater downhill confidence and control.

FEATURES

  • Superior modulation gives you greater control
  • Quicker Piston retraction
  • High braking power instills greater downhill confidence and control
  • Reduces disc brake rotor wobbling noise and increases braking power by 10% (vs. M8000)
  • Four Piston
  • Quick and easy assembly
  • Banjo type connection and inside hose routing

MODEL NOBR-M8120
SERIESDEORE XT M8100 Series
ColorSeries color
Average weight141
Brake typeHydraulic disc brake
Brake hose (kit)SM-BH90-SBM
Hose jointBanjo
Brake hose color (kit)|1Black
J-Kit spec (for OEM)
ICE TECHNOLOGIES pad compatible caliper
Pad|Standard 1N03A-RF Resin (w/ fin)
Pad|Standard 2N04C-MF Metal (w/ fin)
Pad|Option 1D03S-RX Resin (w/o fin)
Pad|Option 2D02S-MX Metal (w/o fin)
Recommended brake leverBL-M8100 BL-T8100
Recommended disc brake rotorRT-MT800
Compatible rotor size|140 mm (SS)
Compatible rotor size|160 mm (S)
Compatible rotor size|180 mm (M)
Compatible rotor size|203 mm (L)
Compatible rotor size|220 mm (LL)
OilSHIMANO mineral
Mount typePost type
Piston4
Caliper fixing screw|Tool size5 mm
Caliper fixing screw|Anti loosen methodSnap ring
Pad mountPad axle























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