diff --git a/python/spi.py b/python/spi.py
index 0ff15c3b..b742f28f 100644
--- a/python/spi.py
+++ b/python/spi.py
@@ -58,7 +58,7 @@ class SpiDevice:
   """
   Provides locked, thread-safe access to a panda's SPI interface.
   """
-  def __init__(self, speed=30000000):
+  def __init__(self, speed):
     if not os.path.exists(DEV_PATH):
       raise PandaSpiUnavailable(f"SPI device not found: {DEV_PATH}")
     if spidev is None:
@@ -87,7 +87,9 @@ class PandaSpiHandle(BaseHandle):
   A class that mimics a libusb1 handle for panda SPI communications.
   """
   def __init__(self):
-    self.dev = SpiDevice()
+    # 50MHz is the max of the 845. older rev comma three
+    # may not support the full 50MHz
+    self.dev = SpiDevice(50000000)
 
   # helpers
   def _calc_checksum(self, data: List[int]) -> int: